Thanks to Tim Reyes for finding this article and sending in a copy for inclusion in the GTC
archives!
Citation: The American Journal of Sports Medicine, Jan-Feb 1994 v22 n1 p
78(5)
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Title: Ankle sprain prophylaxis: an analysis of the stabilizing effects
of braces and tape.
Authors: Shapiro, Matthew S.; Kabo, J. Michael; Mitchell, Peter W.;
Loren, Gregory; Tsenter, Michael
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Subjects: Ankle_Wounds and injuries
Sprains_Care and treatment
Orthopedic braces_Evaluation
Adhesive tape_Therapeutic use
Reference #: A14944008
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Author's Abstract COPYRIGHT American Orthopaedic Society for Sports Medicine
1994
ABSTRACT Five cadaveric ankles were used to determine the effects of
prophylactic bracing and tape on resisting an inversion moment applied to the
ankle. The ankles were tested in neutral flexion and 30 degrees of plantar
flexion and with both low- and high-top shoes. Eight different strap-on braces
were studied. High-top sneakers significantly increased the passive resistance
to inversion afforded by all braces and tape. Many of the braces functioned to
resist inversion at a level that was comparable with or exceeded the
capability of freshly applied tape. This finding was independent of the type
of footwear. Braces that were not as effective as freshly applied tape
nevertheless retained the advantage over tape in that they could be easily
readjusted and their effectiveness restored, whereas the quality of the
support provided with tape deteriorated with usage.
Full Text COPYRIGHT American Orthopaedic Society for Sports Medicine 1994
Ankle sprains are one of the most common injuries treated by orthopaedic
surgeons and athletic trainers. Garrick, [9] in an epidemiologic study of
ankle sprains, found that the lateral ligament complex is the single most
frequently injured anatomic structure in athletes, and that ankle sprains
account for 10% to 20% of the time lost from athletic participation. Jackson
et al. [14] reported that ankle sprains were the most common injury in a group
of military cadets participating in sports.
In most cases, ankle sprains occur as a result of inversion injury. This can
result from an athlete landing on his or her inverted foot or landing on an
opponent's foot or another obstacle. The degree of inversion is amplified by
the follow-through momentum of the body. This situation causes a moment about
the ankle joint, which further inverts the ankle. The ability of an athlete to
effectively fire his or her peroneal muscles may counter this inversion
tendency. If the moment is unchecked, inversion will continue until bony
apposition between the calcaneus and medial malleolus occurs. During this
process, the anterior talofibular and the calcaneofibular ligaments are
loaded, and frequently tear. More severe injuries may rupture the anterior
tibiofibular or deltoid ligaments as well. [5,15]
In an attempt to decrease the incidence of this common injury, physicians and
trainers have used ankle taping as a prophylactic measure. Several studies
have demonstrated the efficacy of ankle taping in terms of restricting motion
of the ankle, as well as decreasing the incidence of ankle sprains. [1,6,10]
Subsequent studies, however, have demonstrated that the effectiveness of ankle
taping decreases rapidly with exercise. Several different reports have
demonstrated a 12% to 50% decrease in the stabilizing effect of ankle tape
after as little as 10 minutes of exercise, [3,8,11,16,17,19] Because of these
disadvantages, as well as cost and time considerations, along with concurrent
improvements in ankle brace design, physicians and trainers have turned to
removable braces as an alternative for ankle injury prevention. [20,22]
Because braces can be reused, they are a much less expensive application.
Additionally, braces can be applied by the athlete, whereas tape must be
applied by a trainer or coach. The brace is easily retightened during use, as
opposed to tape, which must be removed and replaced to restore its
effectiveness. In light of these factors, braces can be expected to maintain
their effectiveness during the entire period of use; tape cannot.
Several studies have shown that braces restrict ankle range of motion as
effectively as tape, and do not lose this effect with exercise. [2, 3, 7, 12,
13, 18, 21] Other studies have also reported that these orthotic devices do
not adversely affect athletic performance. [4,12] Nearly all of these studies
concentrated on evaluating the effectiveness of a particular brace with
respect to the performance of tape, or performed subjective user evaluations.
To date, no study has measured the passive mechanical effectiveness of these
devices. The effect of footwear on the effectiveness of braces has also been
addressed, but the results have been conflicting. Garrick and Requa [10] found
that high-top sneakers reduced the incidence of ankle sprains when compared
with low-top sneakers, but Rovere et al. [21] claimed that low-top sneakers
were better.
The present study addresses these conflicting stabilization issues from a new
perspective. The purpose of this study was to determine the passive mechanical
effectiveness of braces or tape and footwear in resisting ankle inversion. We
designed a system to measure the stiffness added by any combination of brace
or tape and shoe to a cadaveric ankle/foot preparation. In this way we were
able to measure the relative effects of taping and a variety of braces on the
tendency of an ankle to undergo an inversion angulation when loaded. In
addition, we examined the effect of high- or low-top sneakers on the efficacy
of each tape or brace preparation.
MATERIALS AND METHODS
Five male cadaveric ankles between the ages of 20 and 65 years were obtained
from the UCLA willed body program. A physical examination was performed on
each ankle and included an anterior drawer test and tibial talar shift test.
All ankles were radiographically normal. The ankles were prepared for testing
by transecting the tibia and fibula at midshaft and embedding the end of the
bones in a methylmethacrylate cylinder that could be rigidly mounted in the
testing device. The foot was transected at the tarsometatarsal junction. Three
or four 3/16 inch (or greater) diameter Steinmann pins were inserted anterior
to posterior through the calcaneus, and the ends of the pins were embedded in
a methylmethacrylate block that could be rigidly clamped to the footplate
fixturing device.
Taping was done in a standard fashion, using a thin foam underwrap and 2-inch
cloth adhesive tape in a standard figure-8 technique as is commonly employed
in the UCLA Athletic Training Center. Eight commercially available braces were
tested. These were obtained at no cost to the study from the manufacturers.
The braces tested were McDavid Ankle-Guard, A-101 (McDavid, Inc., Clarendon
Hills, IL), Air-Stirrup Ankle Training Brace (Aircast, Inc., Summit, NJ),
Gelcast (Centec Orthopaedics, Division of Royce Medical Company, Agoura Hills,
CA), Super-8 (Pro Orthopaedic Devices, Inc., Tucson, AZ), DonJoy Model FG-062
(DonJoy, Inc., Division of Smith & Nephew, Carlsbad, CA), Eclipse Excel Ankle
Support (Surefit Orthopaedics, Culver City, CA), Ankle Stabilizer (Cramer Gardne
r, KS), and High Top Ankle Support (Technol Products,
Inc., Fort Worth, TX). Braces were applied according to the manufacturer's
instructions. When a lace-up brace was applied, each lace was tightened
sequentially using a scale under tension to 20 pounds. VELCRO straps (VELCRO
USA, Inc., Manchester, NH), when present, were similarly tightened to 10
pounds before being attached.
Each ankle was tested in neutral dorsiflexion without tape or brace in a
standard low- and high-top sneaker. The laces of each sneaker were tightened
in the controlled manner previously described. Each ankle/brace or ankle/tape
preparation was then tested with both types of footwear in an identical
manner. Two repetitions were made for each possible combination with each
ankle. When tape was used, it was replaced for each new footwear application.
To simulate the position of the foot in plantar flexion, a 30 degrees wedge
block was placed under the heel of each sneaker. All tests were repeated for
each possible configuration for each ankle.
The testing device consisted of a footplate mounted on a laterally directed
roller bearing (Fig. 1). The tibial potting was attached to the axial load
cell connected to the fixed cross-member of the MTS-812 materials testing
machine (Materials Test Systems, Minneapolis, MN). The foot and shoe assembly
was positioned on the footplate and locked into place by clamping the plastic
embedded ends of the Steinmann pins directly to the plate. The plate rested on
an axle with two 4-inch diameter wheels. During vertical motion of the MTS
piston, the wheels were guided horizontally along a set of parallel rails. The
foot and plate assembly was free to rotate about the axis of the tibia. Axial
motion of the piston was always initiated with a slight compressive preload
causing the ankle to start from a position of a few degrees of inversion. This
configuration applies a pure force compressive couple that acts through the
wheel axis and the tibial shaft. Slight inversion with a preload ensures a
stable test configuration.
Force was recorded by the load cell mounted on the crossbar, horizontal
displacement was recorded for the w,heel axis with a potentiometer in a
voltage divider circuit, and inversion angle was recorded directly with an
inclinometer attached to the underside of the footplate. Axial (vertical)
displacement was at the rate of 2 cm/min. Ankle inversion was continued until
40 degrees was reached, at which time the piston motion was reversed and the
ankle unloaded. This value was selected to prevent damage to the ligamentous
structures of the ankle. Inversion moment was readily calculated from the
product of the horizontal displacement and the axial load.
The slow loading rate was intended to minimize the viscoelastic response of
the soft tissues so that the effects of our experimental variables could be
determined. Dynamic loadings, which are typically associated with ankle
sprains, would tend to increase the rigidity of the entire system independent
of the brace and footwear.
The sequence of testing each brace or tape construction was performed in the
following order: 1) neutral flexion, low-top shoe; 2) plantar flexlon, low-top
shoe; 3) neutral flexion, high-top shoe; and 4) plantar flexlon, high-top
shoe. The use of a particular brace or tape was randomized. The control state
using a low-top shoe was performed first and repeated again when all other
configurations had been exhausted. Comparison of the initial and final control
state measurements revealed no significant differences and provided direct
confirmation of the preservation of intact joint stability throughout the
tests.
Inversion force, moment, and stiffness (slope of the moment versus angle
curve) were determined for each possible combination of parameters. Regardless
of the measure used, the same general trends were seen in relation to type of
ankle support, type of shoe, and degree of plantar flexlon. Therefore, the
results presented will be restricted to the magnitude of the inversion moment
required to invert the ankle 30 degrees. This angle was selected because the
moment versus inversion angle curves were quite linear (average [R.sup.2] =
0.94) over a large range, indicating a very stable moment angle relationship.
For each foot the inversion moment value at 30 degrees of inversion was
divided by the corresponding average value from the baseline control of bare
foot plus low-top sneaker plus flat configuration on footplate. This
configuration for each foot was selected as the control state for the other
test configurations for the same foot.
To evaluate the braces in relation to the standard that is represented by
ankle taping, the percent change sion moment relative to the taped
condied as
([IM.sub.brace]-[IM.sub.tape IM is the value of the inversion moment obtained fo
r 30 degrees of ankle
inversion.
Mixed-model analysis of variance and t-tests were used to determine
significant differences.
RESULTS
The data are preferentially presented as ratios obtained by dividing the test
data by the average of the values of all of the ankle specimens for a selected
control state. This is preferable to simple percentage changes because
standard deviations can also be presented, which reflects the variation in the
data. For those interested, the percentage change from the control state is
readily obtained from the simple calculation: (ratio - 1) X 100 = percent. In
any event, larger numbers signify a greater difference from the control state.
A summary of the averages of the normalized ratios is presented in Table 1.
Figure 2 depicts the change in the normalized inversion moment ratio as a
function of the ankle test condition (neutral or plantar flexion, low- or
high-top shoe) for the taped ankles and a representative brace. Figure 3
displays inversion moment ratio for the different braces and tape for the
ankle test configuration (neutral flexion, high-top shoe) where the greatest
resistance to inversion was found. It can be readily seen that all braces and
tape were effective in increasing the resistance of the ankles to an inversion
moment. The use of high-top footwear maximizes the protective capability of
the prophylaxis. In all cases, greater force was required to invert the ankles
at 30 degrees when the foot was placed flat.
Figure 4 presents these changes as a function of brace type for both the low-
and high-top footwear for the case of no plantar flexion. The control state is
the foot plus low-top shoe only. All braces and tape significantly (P < 0.05)
stiffened the unprotected ankle in a low-top shoe. The stiffness observed with
the taped ankles represents the highest values possible, as previous studies
have verified that the effectiveness of tape decreases with use.
A greater inversion moment was required with the foot in a flat position than
when in plantar flexion for all configurations except for the unprotected
ankle. Braces and tape, therefore, are more effective in resisting ankle
inversion when the ankle is flat.
For the low-top shoe, flat configuration, all braces and tape provided a more
than two times improvement in the resistance to inversion. This improvement
was significantly higher only for the Super-8 brace design in this
configuration (P < 0.05). As seen for the control state, high-top footwear
provided a doubling of the resistance to inversion, regardless of whether the
ankle was in neutral position or in plantar flexion. Only for the neutral
position was this finding significant (P < 0.001).
In the high-top shoe, flat configuration, while there was considerable
variability, none of the braces were significantly different from tape. The
resistance of the Cramer brace design was less than or equal to the
performance of the taped ankle under all conditions studied, but these
differences were not significant. We caution against a negative interpretation
of this particular result because tape will always loosen and braces maintain
the advantage of a quick retightening.
The DonJoy, Aircast, Gelcast, and tape systems provided a substantial increase
in inversion resistance with high-top footwear for both the neutral and
plantar flexion positions.
DISCUSSION
Prophylaxis of ankle sprains is achieved by diminishing the tendency of the
ankle to undergo inversion. This has always been achieved by stiffening the
ankle joint by application of an external device. Taping with cloth adhesive
tape is still regarded by many sports physicians, coaches, and athletic
trainers as the standard application for the prevention of ankle sprains.
Ankle braces are regarded by some as a less costly way to perform the same
task. Still others claim that braces have distinct advantages over tape.
Whichever device is used, it shares the applied moment with the ankle and
achieves a stiffness that is higher than the ankle alone provides. Stiffness
can also be added by the sneaker that is worn in conjunction with the
prophylactic device. To put it simply, the stiffer the ankle/brace/sneaker
combination is, the less the resultant angulation for a given load.
Additional mechanisms for the function of prophylactic devices are possible.
An external device on the skin may increase the player's proprioception,
causing more effective muscular control. [11] This effect may be a benefit of
high-top sneakers as well. It is also possible that prophylactic devices
prevent the player from landing on an inv the unweighted
foot in neutrgus alignment. Once the foot has a certain degree of
inversion, however, the applied load (such as body weight) will cause an
inversion moment that must be resisted by the inherent stability of the ankle
and any external devices being worn. A stiffer ankle construction will have
less tendency for inversion-induced injury.
Sprains occur clinically in both dorsiflexion and plantar flexion. In certain
situations, only one of the two lateral ligaments is injured. Sprains that
preferentially injure the anterior talofibular ligament probably occur in more
plantar flexion. This position may be associated with injuries that occur when
the player lands on someone else's foot or on uneven ground. With the foot in
more plantar flexion, the distance between the center of rotation (the
tibiotalar joint) and the point of force application (the plantarflexed foot)
is greater; therefore, the inversion moment is correspondingly greater. Thus,
plantar flexion may be a more vulnerable position for ankle sprains. All of
the braces used in this study demonstrated decreased efficacy in plantar
flexion. The magnitude of this decrease was brace- and footwear-dependent.
The effect of a high-top sneaker was to improve the efficacy of the brace or
tape. In all cases, the presence of a high-top shoe required greater force to
invert the ankle. A two-times improvement was observed for an unbraced or
untaped ankle; when brace or tape was added, the benefit of using a high-top
shoe increased further. All braces demonstrated greater than two-times
improvement when used with the low-top shoe, which is comparable with the
improvement afforded to using a high-top shoe without a brace.
Because this was a cadaveric study, the dynamic effects of the stabilizing
muscles cannot be incorporated. Thus, we are able to report only the intrinsic
passive stability provided by these devices. We also are unable to evaluate
the subjective comfort of the devices and therefore cannot comment on the
issue of patient compliance.
CONCLUSIONS
The use of ankle braces and tape affords a dramatic increase in the protection
of the ankle by decreasing the resultant inversion caused by an applied force.
High-top sneakers significantly increase the passive resistance to inversion
afforded by all braces and tape. This effect was smallest for the Cramer
brace. Many of the braces function to resist inversion at a level that is
comparable with or exceeds the capability of freshly applied tape. This
finding was essentially independent of the type of footwear tested. Those
braces that were not as effective as freshly applied tape retain the advantage
over tape in that they can be easily readjusted and their effectiveness
restored, whereas the quality of the support provided with tape deteriorates
with usage. These braces represent good alternative choices for athletes who
refuse to wear high-top sneakers.
ACKNOWLEDGMENTS
The authors thank all of the brace manufacturers who contributed orthoses for
use in this investigation. The authors also acknowledge the assistance of Jim
Zachazewski, PT, ATC, in the implementation and instruction of the proper
ankle taping technique.
REFERENCES
1. Abdenour TEE, Saville WA, White RC, et al: The effect of ankle taping upon
torque and range of motion. Ath Training 14: 227-228, 1979
2. Beynnon BD, Renstrom P: The effect of bracing and taping in sports. Ann
Chir Gynecol 80: 230-238, 1991
3. Bunch RP, Bednarski K, Holland D, et al: Ankle joint support: A comparison
of reusable lace-on braces with taping and wrapping. Physician Sportsmed
13(5): 59-62, 1985
4. Burks RT, Bean BG, Marcus R, et al: Analysis of athletic performance with
prophylactic ankle devices. Am J Sports Med 19: 104-106, 1991
5. Colville MR, Marder RA, Boyle JJ, et al: Strain measurement in lateral
ankle ligaments. Am J Sports Med 18: 196-200, 1990
6. Delacerda FG: Effect of underwrap conditions on the supportive
effectiveness of ankle strapping with tape. J Sports Med 18: 77-81, 1978
7. Friden T, Zatterstrom R, Lindstrand A, et al: A stabilometric technique for
evaluation of lower limb instabilities. Am J Sports Med 17:118-122 1989
8. Fumich RM, Ellison AE, Guerin GJ, et al: The measured effect of taping on
combined foot and ankle motion before and after exercise. Am J Sports
Med 9: 165-170, 1981
9. Garrick JG :The frequency of injury, mechanism of injury, and epidemiology
of ankle sprains. Am J Sports Med 5: 241-242, 1977
10. Garrick JG, Requa RK: Role of external support in the prevention of ankle
sprains. Med Sci Sports 5: 200-203, 1973
11. Glick JM, Gordon RB, Nishimoto D: The prevention and treatment of ankle
injuries. Am J Sports Med 4:136-141, 1976
12. Greene TA, Hillman SKsupport provided by a semirigid
orthosis and adhesive ankle taping before, during, and after exercise. Am J
Sports Med 18: 498-506, 1990
13. Gross MT, Bradshaw MK, Ventry LC, et al: Comparison of support provided by
ankle taping and semi rigid orthosis. J Orthop Sports Phys Ther 9: 33-39, 1987
14. Jackson DW, Ashley RL, Powell JW: Ankle sprains in young athletes.
Relation of severity and disability. Clin Orthop 101:201-215, 1974
15. Johnson EJ, Markolf KL: The contribution of the anterior talofibular
ligament to ankle laxity. J Bone Joint Surg 65A: 81-88, 1983
16. Laughman RK, Carr TA, Chao EY, et al: Three-dimensional kinematics of the
taped ankle before and after exercise. Am J Sports Med 8: 425-431, 1980
17. Malina RM, Plagenz LB, Rarick GL: Effect of exercise upon the measurable
supporting strength of cloth and tape ankle wraps. Res Q 34: 158-165, 1963
18. Myburgh KH, Vaughan CL, Isaacs SK: The effects of ankle guards and taping
on joint motion before, during, and after a squash match. Am J Sports Med 12:
441-446, 1984
19. Rarick GL, Bigley G, Karst R, et al: The measurable support of the ankle
joint by conventional methods of taping. J Bone Joint Surg 44A: 1183-1190,
1962
20. Renstrom P: Sports traumatology today. A review of common current sports
injury problems. Ann Chir Gynecol 80: 81-93, 1991
21. Rovere GD, Clarke TJ, Yates CS, et al: Retrospective comparison of taping
and ankle stabilizers in preventing ankle injuries. Am J Sports Med 16:
228-233, 1988
22. Tropp H, Askling C, Gillquist J: Prevention of ankle sprains. Am J Sports
Med 13: 259-262, 1985
[TABULAR DATA OMITTED]
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Citation: Physical Therapy, Jan 1994 v74 n1 p17(15)
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Title: Local sensation changes and altered hip muscle function following
severe ankle sprain. (includes commentary and author response)
Authors: Bullock-Saxton, Joanne E.; Leonard, Charles T.
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Subjects: Ankle_Dislocation
Hip_Muscles
Sprains_Physiological aspects
Muscle strength_Measurement
Reference #: A14737290
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Author's Abstract COPYRIGHT American Physical Therapy Association Inc. 1994
Background and Purpose. Changes in sensory information have been shown to
influence muscle function locally. Some clinicians, however, believe that the
influence may be more extensive. To investigate this clinical concept,
subjects with severe ankle sprain were assessed for local sensation changes
and proximal hip/ back muscle function. Subjects. Of a total of 361 potential
subjects whose medical histories were assessed, 20 men (age 18-35 years) who
had previously sustained a severe unilateral ankle sprain and 11 matched
"control" subjects with no previous lower-limb injury participated in the
study. Methods. Using this experimental model, ten of vibration vibration in
the ankle (indicating sensation changes) as well as surface electromyography
of muscle recruitment patterns for hip extension (indicating muscle function
proximally) of the biceps femoris, gluteus maximus, and lumbar erector spinae
muscles were made on both sides of the unilaterally injured and matched
control subjects. Results.Significant decreases in vibration perception and
significant delays in gluteus maximus muscle recruitment during hip extension
were found in the injured group. Conclusion and Discussion. The author
concludes that both local sensory and proximal muscle function changes are
associated with unilateral severe ankle sprain.
Full Text COPYRIGHT American Physical Therapy Association Inc. 1994
Key Words: Ankle; Electromyography; Hip; Muscle performance, lower extremely;
Sensation; Sprains and strains.
The existence of a complicated feedback system between muscles and joints and
the central nervous system is well recognized. Interference with sensory
feedback may affect a person's ability to monitor movements or to make
appropriate adaptations and adjustments to movement. For example, a change in
postural stability when a person stands on one leg following ankle sprain was
attributed by Freeman[1] to altered proprioceptive input from the ankle joint
and its influence on the postural control of the muscles.
This relationship between joint receptor information and muscle function has
interested researchers for some years, and the relationships between
stimulation of joint afferents and muscle activity have been demonstrated in
both animal and human studies.[2-5] For example, Ekholm et al[2] investigated
the response to various articular stimuli of decerebrate and, in some
instances, spinalized cats. They found that increasing the articular pressure
in the knee joint, as well as pinching its capsule, led to decreased
quadriceps femoris muscle (ie, extensor) activity, whereas pinching the knee
capsule elicited an increased response from the knee flexors (biceps femoris
muscles). In their study of human subjects, Stokes and Young[3] considered
that joint injury can decrease the activity of muscles, leading to weakness
and wasting. They measured the rectified integrated electromyographic (EMG)
activity of both quadriceps femoris muscles of patients who had a meniscectomy
or an arthrotomy and recorded large decreases (80%) in quadriceps femoris
muscle activity on the side of surgery. This effect persisted for up to 15
days postoperatively 30%-40%), despite the lack of pain at that time.
A possible mechanism for this decreased activity might be the excitation of
joint afferents in the capsule because of pressure caused by joint infusion.
Indeed, in 1965, De Andrade et al[4] showed that in healthy human subjects and
in those with pathology, infusion of saline into the knee joint was
responsible for decreased activity of the quadriceps femoris muscles. Results
of recent studies by Iles et al[5] have indicated that as the volume of saline
infused into the human knee joint is increased, the amplitude of the H-reflex
is decreased and that even apparently imperceptible volumes of saline could
decrease quadriceps femoris muscle activity. In these studies, the decrease of
extensor activity following afferent stimulation was highlighted.
The relationship between ankle articular mechanoreceptor function and the
reflex activity in the limb of the cat was also investigated by Freeman and
Wyke.[6] Establishing the normal reflex muscular response of the tibialis
anterior and gastrocnemius muscles, these researchers decreased the afferent
information from the joint by local anesthesia and by electrocoagulation of
the articular tissues. Both procedures caused an abolition of the normal
reflex muscular response to movement, indicating the importance of articular
information to regulation of muscle activity. Freeman and Wyke[6] believe that
muscle activity is regulated through the contribution of the articular
impulses to a facilitatory bias to the gamma motoneurons of the muscle
spindles. If such an influence exists, then their early assertion that
articular afferents influence local muscle activity is correct and has been
supported by the later research of Iles et al.[5]
This experimental evrts the clinical observation that a joint
injury involving sensory receptors can influence the muscle function about
that joint. However, a more complex relationship than this has also been
proposed. This proposed relationship is that altered sensation in one joint
could lead to muscle function changes in another more proximal joint. This
concept has been the basis of teaching by Lewit[7] and Janda[8] for several
decades. Some experimental data on cats do exist demonstrating that the motor
system has a tendency to extend dysfunction into a larger area.[9]
Although difficult to extrapolate results from animal studies to human
behavior, Wyke[9] observed that in the cat, an injury of the joint capsule or
ligaments influences muscle activity not only in muscles that cross the
injured joint, but also in remote muscles. Wyke stated that
... interruption of the flow of impulses
from the mechano-receptors in a joint
capsule into the central nervous system
should result in clinically evident disturbances
of perception of joint position
and movement and of the reflexes
concerned with posture and gait.[9](p44)
Thus, the arthrokinetic reflex might be considered as a triggering factor that
would initiate a whole chain of adaptation reactions, eventually resulting in
a changed movement pattern. The possibility that sensory deficits associated
with localized injury in one part of the body influence muscle function in
another and may ultimately lead to pain has considerable implications for the
physical therapist, influencing both the preventive and therapeutic approaches
to patient care.
Wyke[9] also argued that articular sensory information is vital to normal
postural reflexes. He cited observations of impaired postural reflex activity
of muscles following severe ankle sprain of humans and proposed that this
might be a reflection of the impaired proprioceptive information from the
damaged mechanoreceptors. As afferent impulses travel to cerebellar and
cortical centers,[10] the impaired afferent information from the ankle joint
may be sufficient to impair the motor regulation of body posture. In their
experimental study of postural stability following ankle sprain, Tropp et
al[11] found a significant decrease in postural stability when compared with
noninjured subjects, thus confirming Wykes'[9] observations. Recent
experiments by Gauffin and colleagues[12] have indicated that patients with
unilateral anterior cruciate ligament injury demonstrated bilateral
alterations in their postural control when compared with uninjured subjects.
They postulated that these alterations may be due to "central adjustments of
motor control." The postulation that changes in sensory input could cause
alterations in the function of muscles in a joint remote from the injury seems
to be well justified, although no direct experimental evidence of this in
humans has yet been reported.
This study was conducted, therefore, to investigate whether a localized lesion
at a peripheral joint such as the ankle influenced the sensation in that area
as well as the muscle function in more proximal regions such as the hip and
pelvis and, if so, whether such changes were interrelated. The sensory and
muscle function in both limbs of subjects who had previously sustained a
severe unilateral ankle sprain was compared with that in both limbs of
noninjured ("control") subjects.
For this study, appropriate tests of sensory and muscle function needed to be
selected. Freeman et al[13] theorized that ankle instability following injury
develops primarily due to lesions of mechanoreceptors in the joint capsule and
ligaments. This instability impairs both the static position and joint
movement sense. This theory was not supported by Gross,[14] who compared
active and passive joint position sense in both injured and uninjured subjects
and found no significant difference between them. However, the method of
testing used for assessing joint position sense involved strapping the foot to
a movable footplate with firm pressure. It is possible that mechanoreceptors
on both plantar and dorsal surfaces of the foot, which were not compromised by
the lateral ligament ankle injury, were able to provide sufficient cues for
the subject to determine ankle joint position. Barrack and colleagues[15]
appear to have developed a successful measurement procedure for eliminating
pressure cues during testing of joint position sense of the knee following
anterior cruciate ligament injury. These researchers found significant
deficits in joint position sense of the knee.
If damage to sensory receptors from severe ankle joint sprain is to be
accurately measured, a test that is sensitive to changes in sensory receptos nee
ded. Two factors were considered ingard: (1) the
influence of joint stress on discharge rates of mechanoreceptors and (2) the
effects of age on sensation. Wyke,[9] in his description of three types of
articular nerves, outlined how the frequently occurring group II nerve fibers
terminated onto both low-threshold, slowly adapting mechanoreceptors (type 1)
and low-threshold, rapidly adapting mechanoreceptors (type II). The type I
mechanoreceptors, found in clusters around the joint capsule, where the
greatest degrees of stress during movement are likely to occur, are sensitive
to changes in joint pressure and position. Their rate of discharge adapts
rapidly to the degree of joint stress. It is likely that capsular tears,
rupture of small nerve fibers, and joint edema following ankle sprain could
cause alterations of discharge from these receptors, as indicated by Freeman
et al.[13]
In persons without joint injuries, perception of some superficial and deep
sensations decreases with age. These sensations include tactile, two-point
discrimination; vibration perception; and joint movement sense.[13] Such an
age-related decline suggests that these sensory modalities are vulnerable to
change. Vibration perception requires information from both superficial and
deep mechanoreceptors as well as a functional cortical sensory association
area.[16] Testing vibration perception, therefore, would provide information
on the integrity of sensory receptors possibly damaged due to ankle
ligamentous injury. This assessment of sensation is capable of a high degree
of control in comparison with current tests used for assessing tactile,
two-point discrimination or joint movement sense around the ankle. For these
reasons, vibration perception was chosen as the variable for assessment of
sensory function in this study.
Muscle function in each limb was investigated in terms of the temporal
sequence of activation (as illustrated in EMG signals) of the gluteus maximus,
hamstring, and ipsilateral and contralateral lumbar erector spinae muscles
during the movement of hip extension from a prone-lying position. Janda[17]
has claimed that the determination of the order of activation of muscles
performing a simple movement is important for the understanding of the methods
used by patients to move their body and that this knowledge helps to reveal
the area of impairment. Hip extension was selected for this study, not only
because the studied muscles were separated from the site of injury but also
because of its functional importance in stance and locomotion. Due to the
complexities of the gait process, it was considered advisable to isolate the
hip extension motion rather than to study muscle function during gait. Much
greater control could be imposed experimentally by assessing muscle activation
during hip extension from a prone-lying position than would be possible during
locomotion.
In my study, the effects of ankle sprain (the independent variable) on
vibration perception at the ankle and the pattern of activation of specified
muscles around the hip and low back (the dependant variables) were measured. A
matched control group was used for comparison. Only subjects who had sustained
a unilateral ankle sprain were included in the injured group, so that
side-to-side differences between their injured and uninjured sides could be
compared with the normal side-to-side differences demonstrated in the
uninjured control group.
Method and Materials
Subjects
Two groups of subjects were studied: an "injured" group, who had previously
sustained a severe unilateral ankle sprain, and a matched "control" group, who
had no previous lowerlimb injury. To control variables between the two groups
of subjects, a suitable population of sufficient size was sought. The armed
forces provided such a source. The Australian Defence Force (Army) gave
permission for their soldiers and officers to volunteer to be subjects for
this study.
For the injured group, subjects were included if they had previously sustained
a grade II+ or III (severe or unstable[18]) lateral ankle sprain that was
significant enough to have caused marked swelling at the time of injury and
discomfort while walking. Treatment must have included a period of
immobilization. The subjects' right side must also have been the preferred (or
"skill") side. Subjects were excluded if they had had a significant injury to
any other lower-limb joint or a significant injury to either leg. Of
particular concern was the need to exclude subjects who may have had a history
of incoordination or clumsiness (operationally defined as a history of sensory
and/or motor dysfunction not related to injury, in the absence of intellectual
impairmas essential to ensure that an existing neurological deficit
was not a predisposing cause of the ankle sprain, because the finding of
differences in localized sensory function in the control group could then be
said to be a cause, rather than an aftereffect, of the injury.
I assessed the medical histories of 361 potential subjects; 80 subjects (22%)
were found to have sustained an ankle sprain on both sides, and 233 subjects
(65%) either had injuries in other joints or were unavailable to participate
in the study. Sixty-four men (18%) underwent the detailed screening process,
but only 20 (6%) of these subjects met all inclusion criteria.
Variables measured were age, physical characteristics such as height and
weight, and level of physical activity (eg, during sports and work). Subjects
for the control group, who matched subjects in the injured group in these
characteristics, were sought from the same army units. Eleven men fitting the
criteria were found. Table 1 illustrates the distribution of relevant
variables between the two groups.
[TABULAR DATA OMITTED]
Measurement
Vibration perception. Dyck et al[19] have discussed the problems associated
with the measurement of the threshold of vibration perception and the
inadequacy of current clinical methods (such as the use of tuning forks) in
providing reliable, repeatable results. For my measurements of vibration
sensitivity, it was desirable to ensure that frequency and amplitude of
vibration could be varied, a consistent pressure of application could be
maintained, and the subject could remain alert and cooperative. To meet the
first of these criteria, a mechanical oscillator(*) connected to a Power
oscillator(dagger) was used. This instrument allowed variation of both
frequency and voltage and provided measures of output voltage directly related
to acceleration (force intensity) of the oscillator head at each of the chosen
frequencies. To ensure a constant pressure of this device on the skin, the
oscillator was suspended from one end of a system of pulleys and a mass of
equal weight was suspended from the other end as a counterbalance.
The subject was positioned side lying with the leg to be tested uppermost and
secured in a lower-leg rigid support (back slab) to control the degree of
ankle dorsiflexion, and supported on a high-density foam cushion Fig. 1). The
oscillator was positioned perpendicular to and just touching a point on the
inferior fibular head, and the weight on the counterbalance was reduced by 50
g. The head of the oscillator, therefore, made contact with the fibular head
with a gravity-applied force of 50 g. The voltmeter, which reflected the
amplitude of oscillation of the vibrator, indicated both when vibration was
occurring and when it had ceased.
Because there appears to have been little research into the perception of
vibration at different frequencies, a range of frequencies (ie, 100, 150, 200,
and 250 Hz) was assessed. For each frequency, the oscillator amplitude (which
could be termed "vibration strength") was slowly increased until the subject
stated that he perceived vibration. This voltage was recorded as the
threshold. Two measurements at each frequency were taken on one limb to
provide an estimate of measurement error, before commencing the series on the
second limb. The order of presentation of the series of frequencies to each
subject and between subject sides was randomized. One researcher (JEB-S)
tested all subjects.
To determine the consistency of subject threshold to vibration perception, a
repeatability test was carried out prior to the major study. Ten repetitions
at each frequency on one limb were chosen randomly from a subset of the sample
composed of five injured group subjects and five control group subjects. The
repetitions of each frequency were taken within a 1-hour time span with a
30-second interval between repetitions. The confidence interval limits of the
means (mean[+ or -] t x standard error) and their standard deviations of the
within-subject - between-replication" variation (derived from a suitable
analysis of variance) for each frequency were comparable for each group and
are listed in Table 2. These results indicated that for uninjured subjects and
for those with previous ankle injury, the threshold of vibration perception at
each frequency was repeatable on the one day.
[TABULAR DATA OMITTED]
Muscle activation. Surface EMG was used to provide information regarding the
activation of the specified muscles during hip extension, utilizing bipolar
surface electrodes (silver-silver chloride) on each of the ipsilateral and
contralateral lumbar erector spinae, gluteus maximus, and hamstring muscles of
both limbs. With subjects positionedg, EMG sites were identified,
and electrre placed 10 mm (0.39 in) apart on each prepared site. The
electrodes were positioned parallel to the line of the muscle bellies and over
the area of greatest muscle bulk, determined after a resisted contraction of
the specific muscle. Lumbar erector spinae muscles were monitored adjacent to
the intervertebral level of L2-3, the upper fibers of the gluteus maximus
muscle were monitored, and electrodes were placed on the hamstring muscles
over the biceps femoris muscle. For each hip extension motion, signals from
the four muscle groups were preamplified using a Medelec PA65
preamplifier(double dagger) before passing to a Medelec AAM63
amplifier/filter.(double dagger) The signals were sampled at a rate of
2,500.Hz, were bandpass filtered at a lower frequency of 0.8 Hz and a higher
frequency of 800 Hz, and were recorded on an eight-channel ink jet chart
recorder(section) for monitoring of the signal during data collection. The EMG
signals were also passed to an analogue-to-digital converter in a computer and
stored for analysis.
The starting position of each leg was traced onto a sheet of paper placed over
the base of the test bed to ensure a consistency of position. A feedback
system was devised to assist the subject in controlling his own range of
motion. An inclinometer(parallel) provided a recording of the motion of the
limb during hip extension. The inclinometer was connected to an oscilloscope
positioned below a face hole in the test bed to be monitored by the subject.
The inclinometer produced an output in the form of a moving line on the
oscilloscope, and an initial zero "base" line (representing the limb in
neutral) and a "target" line (representing the designated 15[degrees] range of
hip extension) were marked. Thus, the subject had feedback for the position of
his limb as he moved the limb through the range of motion.
The inclinometer, fixed to a curved metal plate, was strapped to the lateral
side of the thigh on a line between the greater trochanter and the lateral
femoral condyle with the femur in a horizontal position, so leading to zero
output of the inclinometer (giving the base line). Passive limb movement to
the edge of a 15-degree template allowed the 15-degree target line trace to be
recorded on the oscilloscope. When the subject moved his limb, a third
(moving) line provided feedback of the limb's position in relation to the
target line. By connecting the inclinometer to the chart recorder and
computer, the position of the limb was recorded at rest and during movement.
Speed of motion was controlled by the subject moving the limb through the
15-degree range of motion at a rate equal to three beats of a metronome set at
72 beats per minute. That is, the limb moved through a 6-degree arc of motion
per second, which was considered to be approximately equal to a slow walking
speed.
Subjects were encouraged to relax prior to the hip extension, the chart
recording indicating whether the muscles were at rest. Only then was the trial
commenced, with EMG signals being recorded for a count of three beats of the
metronome prior to the request to extend the hip. This initial "at rest"
recording not only provided a base line signal prior to hip extension, but
also allowed the EMG recording of any activity within the muscle as the
subject prepared to move into hip extension. An initial training period
ensured that the subject understood what was required of him. For each
subject, a 10-second recording of EMG and inclinometer signals was made during
each of the six tests on each side. A 10-minute interval separated the tests
on the two sides to allow recovery from any possible fatigue. The same
researcher carried out all testing.
For analysis of EMG data, the order of muscle activation represents the
sequence of each muscle's entry into a coordinated muscle activity. Visual
observation is the method usually used by researchers for this determination.
For this study, however, it was important for statistical purposes to find a
quantitative measure that would allow comparison between groups of subjects of
the relative behavior of muscles contributing to a group activity.
Because one or more muscles might contract prior to the commencement of hip
extension and the starting point of individual muscle contractions relative to
hip motion might vary, a consistent reference point for comparison purposes
was needed. Therefore, the commencement of hip movement (H) was taken as a
reference. The temporal measure used to recognize this was the time span (in
seconds) between onset of individual muscle activity (O) and commencement of
hip movement (H), as determined by the inclinometer (ie, O-H).
Calculation of the time span between points of onset of the fth
muscles provided a second quantitati measure in relation to muscle
activation, allowingtion of whether injury influenced the time
taken for activation of all four muscles. The second temporal measure used,
therefore, was the time span (in seconds) for the sequence of activation of
the first ([Msub1) and fourth ([Msub4) muscles ([O, Msub1-Msub4]). The
incorporation of a time reference into the sampling procedure and the computer
acquisition of EMG and limb-position data allowed for a determination of these
temporal measures.
The EMG signals collected from the four monitored muscles during hip extension
were submitted to computer analysis to determine these measures for each of
the two limbs during the six trials for each subject. A special-purpose
computer program (language C) was written, in which the 2,500 samples of data
per second for each muscle for the 10-second recording period could be
analyzed. Data used for this program related to the raw EMG signals, the EMG
gain used to acquire data, the period for which the data were recorded, the
number of channels used, and the data rate. The number of data points was
calculated and then read in binary format. The data were stored after
multiplication by 100 to enable the program to use integer arithmetic where
possible in the analysis. The mean of the first 500 points was calculated and
subtracted from the raw data to enable the data to be centered on zero. The
data were then rectified about this mean value and smoothed (four passes,
100-point bandwidth) to remove the high-frequency components of the bursts yet
still leave the main burst shape. The filtering process was carried out by
using a filter subroutine that used a rectangular filter (the data were
linearly averaged over the bandwidth of the filter) and that allowed multiple
passes over the data.
The mean of the first 500 points was again calculated and subtracted from the
data to ensure that the mean value of the initial region was zero. The
location of the peak data point was identified, and from this data point, the
times at which the signal reached specified percentages of maximum could be
determined. For the purposes of this analysis, 5% of die maximum (peak value)
EMG signal was regarded as the onset of muscle activity. A second computer
program was used to rank the order in which each of the four muscles was
activated in each case. From this, the O, [Msub1]-[Msub4] calculation was
made. It also provided the incidence of each muscle occurring in each ranked
position.
As a preliminary investigation of onset times, prior to adopting the use of
the computer analysis, an independent "blind" visual observation of the EMG
signals on an IBM-compatible personal computer screen for a random selection
of subjects, trials, and muscles was performed to compare the accuracy of the
computer analysis with human inspection. For the gluteus maximus and hamstring
muscles, the computer analysis was found to give comparable results to those
obtained through manual inspection of the computer-displayed signal, suitably
magnified. Onset data for the lumbar erector spinae muscles were scrutinized
visually to determine those trials in which the proximity of the heart beat
signal to the signal of muscle activity made computer discrimination of the
onset of muscle activity impossible. In such cases, the onset data were
removed from the data set. Of the 372 possible values for muscle onset in the
entire sample, 24 values were rejected for this reason, as reflected in the n
values presented in Tables 3 and 4.
To determine the repeatability of the time of onset relative to hip motion, a
study was carried out using the analysis of six movement repetitions for each
subject. An analysis of variance was applied to determine the mean confidence
interval and its standard deviation and the "within-
subject-between-replication" variability for each of the four muscles. Results
demonstrated an acceptable level of repeatability of the measurement (Tab. 3).
[TABULAR DATA OMITTED]
Data Analysis
Data acquired for muscle activation during hip extension and for vibration
perception for both limbs were analyzed to investigate any differences between
the injured and control groups in muscle or sensory function in each limb. The
general linear model (GLM) of analysis of variance for unequal numbers was
selected as the most appropriate form of analysis for these data. This model
is used to reveal the influence of any independent variable on the dependent
variable and demonstrates whether there is any significant difference between
two groups of unequal numbers. The statistical package used was the SAS for
Personal Computers.(#)
Initially, to determine any group differences in vibration perception,
comparisonn strength required for subject perception at each
frequency were made between the injured and control groups by consolidating
the data for the two limbs in each case. Accordingly, "group" was included as
an independent variable in the GLM analysis. Similar comparisons were made
between groups for each of the two EMG measures. These analyses of the data do
not reveal whether differences exist in one side or the other, or in both, but
only that overall some alterations in vibration perception or in muscle
activation may be associated with injury.
Secondly, to determine whether vibration perception or muscle activation in
the injured or uninjured limb was significantly different from that on either
side of the control group subjects, further analyses were undertaken comparing
the side-to-side differences between groups.
Results
Vibration Perception
Analysis of data for vibration perception at each frequency demonstrated a
significant difference between the injured and control groups (P<.001). As
Figure 2 demonstrates, vibration strength needed to be greater for the injured
group than for the control group in order for the subjects to perceive the
stimulus.
A comparison of side-to-side differences between groups (uninjured versus
injured) showed that whereas there were significant differences between left
and right sides at only one of the four frequencies (200 Hz) for the control
group, there were significant differences between injured and uninjured sides
at three of the frequencies (150, 200, and 250 Hz) for the injured group (Tab.
4).
[TABULAR DATA OMITTED]
Comparison of the mean values for each side of the injured group subjects with
those of each side of the control group subjects showed that a greater
strength of vibration was necessary to reach threshold perception on both the
injured and uninjured sides of the injured group subjects than on either the
left or right side of the control group subjects. To determine whether the
threshold perception values for the uninjured side of the injured group
subjects contributed to these group differences, Student's t tests were
applied to the uninjured side of the injured group subjects versus each side
of the control group subjects. Significant differences were found to exist at
all frequencies (P<.05) (Tab. 5).
[TABULAR DATA OMITTED]
Electromyographic Analysis
Separate statistical analyses were performed on data for each temporal
variable (ie, O-H; O, [Msub1]-[Msub4]). To determine whether there were
significant differences between the injured and control groups, a GLM4
analysis was performed.
O-H. Reflecting the preparatory activation of the muscles prior to the limb
motion in hip extension, the onset times for each of the four muscles in
almost all instances preceded the time of commencement of the reference
activity (ie, hip motion), giving a negative value for O-H. The greater the
negative time span, the earlier the onset of activity of that muscle prior to
hip extension motion, whereas the smaller the negative time span, the later
the onset. The results of analyses of this variable need to be interpreted
with this in mind. Figure 3 represents typical EMG recordings of a control
group subject and an injured group subject.
With the data for the two sides consolidated, the GLM analysis showed that for
the gluteus maximus muscle, highly significant differences existed between the
injured group (mean = - 0.092) and the control group (mean=-0.349) (P<.001),
the time of onset of gluteus maximus muscle activity being significantly later
for the injured group than for the control group. That is, for the injured
group subjects, an overall delay in activation of the gluteus maximus muscle
was evident. For the hamstring and the left and right lumbar erector spinae
muscles, results of the GLM analysis showed that the group differences were
not significant.
The analysis of side-to-side differences for the gluteus maximus and hamstring
muscles revealed that for the control group, the time span (O-H) was
significantly greater on the left (stance) side than on the right (preferred
or skill) side (P<.05), indicating an earlier onset of gluteus maximus and
hamstring muscle activity on the left side for uninjured subjects (Tab. 6).
The side-to-side differences (injured versus uninjured sides) in the injured
group did not reach significance for either of these muscle groups. The
significantly later time of onset of gluteus maximus muscle activity for the
injured group compared with that of the control group (ie, with data for two
sides consolidated), however, suggested a delay in gluteus maximus muscle
activation on both sides of the injured group subjects. Examination of the
data in Tabl that this was so. A Student's t tes
the gluteus maximus muscle activity onset data for the uninjured side of the
injured group versus each side of the control group highlighted the
significant difference that existed (P<.0005). No significant side-to-side
differences were found to exist for either the left or right lumbar erector
spinae muscles.
[TABULAR DATA OMITTED]
O, [Msub1]-[Msub4]. Analyses of the consolidated data relating to the time
span between the onset of activity of the first and fourth muscles ([O,
Msub1-Msub4]) to be recruited revealed highly significant difference (P<.001)
between the injured and control groups. As Table 7 demonstrates, although the
mean time span for the control group was 0.036 second, it was 0.527 second for
the injured group, or 72% longer than for the control group.
The GLM analysis showed that there was no significant difference between sides
in the O, [Msub1-Msub4] time span for either group. Examination of the ranking
incidence indicated that the gluteus maximus muscle was almost always the
fourth muscle to be activated. This delayed activation was therefore
responsible for the greater O, [Msub1-Msub4] time span found in the injured
group.
The delayed activation in the gluteus maximus muscle was used as the variable
for a correlation analysis of muscle and sensory function. A Pearson
Product-Moment Correlation Coefficient analysis was applied to data for both
groups relating to vibration strength at threshold perception level and the
timing of onset of gluteus maximus muscle activity relative to hip extension
(O-H). Results demonstrated that a positive correlation existed for the
injured group between threshold vibration perception and gluteus maximus
muscle activation for the 250-Hz frequency (P<.05). That is, the less
sensitive the subjects were to vibration at 250 Hz, the longer the delay in
recruitment of the gluteus maximus muscle for hip extension. !!!BEGIN TABLE
Table 7. Comparison of Mean Time Span Between Onset of Activity of First and
Fourth Muscles.
Group N X (S)
Control (n= 11) 120 .306(a)
Injured (n=20) 229 .527(a)
[t.sub.df.sup.a]of error in ANOVA=6.73, P<.001. !!!END TABLE
Discussion
Significant differences in the sensory and muscle function of subjects with
severe ankle sprain were shown to exist when compared with that of uninjured
subjects. The decreased ability to perceive vibration appears to confirm the
views of Freeman[1] and Wyke[9] that a ligamentous/capsular injury influences
the integrity of local sensory receptors on the side of injury, presumably
through direct damage.
The significant delay in activation of the gluteus maximus muscle in the
injured group subjects and the positive correlation between a poorer
perception of vibration at 250 Hz and gluteal muscle delay suggests that joint
injury involving sensory receptors could influence the function of muscles
proximal to and removed from the injury side. Even though this study could not
determine cause and effect, this association provides support for the idea of
a reflex chain of events that occurs following injury, as proposed by Lewit[7]
and Janda.[8]
The normal activation behavior of the hamstring and lumbar erector spinae
muscles in the injured group can be viewed together with the delay in
activation of gluteus maximus muscle. A change in activation of all muscles
could have led to the assertion that all subjects in the injured group had a
motor regulation problem, as has been intimated by previous studies.[11,12]
The finding of significant activation changes in the gluteus maximus muscle,
however, only points to the possibility that such a change is associated with
the ankle injury. Because cause and effect were not the focus of this study,
further research is warranted to help clarify these interrelationships.
Differences in vibration perception and activation of the gluteus maximus
muscle on the uninjured side as well as the injured side of the injured group
subjects when compared with the control group subjects support the concept of
central adjustment of motor control following injury. This finding suggests
that a reflex chain of events is not limited to the side of injury, but that
there could also be implications for influences on the uninjured side.
These results suggest that as a result of injury to the ankle joint, the
activity of the hip extensors on both sides of the body is diminished. Whereas
Stokes and Young[3] and Iles et al[5] have demonstrated decreased extensor
activity at the site of injury, the results of this study suggest that there
could be a direct relationship of decreased activity of the extensors of thving
muscles not only remote from the site of injury but also
on the opposite side of the body. It is also possible that even after pain
following the ankle injury had ceased, the function of the gluteus maximus
muscle in extending the hip was compromised due, perhaps, to an alteration in
gait pattern established during the period of injury. Such possibilities are
the subject of further research.
The question could be asked whether subjects in the injured group had a basic
neurological deficit that led to their initial ankle sprain. Every attempt was
made to ensure that injured subjects included in this study had no history of
incoordination. As has been shown by this study, the injured group subjects
did, however, have a sensory deficit compared with the control group subjects.
Although it has been assumed that any differences from normal in the injured
group occurred as a result of injury, in a retrospective study the origin of
the differences cannot be determined. From the point of view of the management
of patients following ankle sprain, however, the origin of the deficit does
not affect the need for the physical therapist to pay due attention to the
need to improve sensory and motor function.[20]
This study has a number of implications for the physical therapist. In view of
the likelihood that a deficit in sensory function is associated with decreased
muscle activity around other joints, a rehabilitation program should include a
focus on improving sensory function. Because muscles respond in different ways
to peripheral injury, the results of this study suggest that the effects need
to be sought in areas remote from the site of injury. This study has examined
only some of the muscles around the hip. Further investigations could reveal
whether muscle function changes also occur in other joints following ankle
injury (eg, in the knee or vertebral joints), or indeed, whether they might
occur as a result of the effects of gluteal muscle delay.
The differences in sensory function and in the function of some muscles on the
uninjured side are also important in treatment. Whether such differences are
due to dysregulation at the cortical level or at a spinal level has still to
be determined. Nevertheless, the existence of differences highlights the need
to examine both sides of the body in assessment. These results emphasize the
importance of the physical therapist paying attention to motor control and to
the function of muscles around joints separated from the site of injury.
Conclusion
The results of this study have shown that both local sensory and proximal
muscle function changes are associated with unilateral severe ankle sprain and
that when some aspects of sensory and motor function deficits are considered,
there is a positive correlation between the two. If comprehensive and
effective management of injury is to be ensured, a holistic approach to
assessment is essential.
(*)Derriton (VP2) Mechanical Oscillator, Derriton Electronics Ltd, Sedlescombe
Rd, St Leonardson-Sea, Sussex, United Kingdom.
(dagger)Goodman's Power Oscillator (D5), Goodman Industries Ltd, Vibration
Division, Axion Works, Wembley, Middlesex, United Kingdom.
(double dagger)Medelec Ltd, Old Working Rd, Surrey, United Kingdom.
(section)Simens AG Minograph Chart Recorder, ZW22, Postgach 101212, D-8000,
Muchen 1, Federal Republic of Germany.
(parallel)Schaevitz (A411-0001) Accelerometer, Applied Measurement, Baltec
Systems, 26 Mayneview St, Milton, 4064, Brisbane, Queensland, Australia.
(#)SAS Institute Inc, PO Box 8000, Cary, NC 27511.
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function for chronic low back pain patients. Spine, 1993;18:704-708.
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Press for more (? for help) ! scroll
Citation: Patient Care, Feb 29, 1992 v26 n4 p6(15)
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Title: Ankle: don't dismiss a sprain. (includes related article on
exercises that help an injured ankle) (Joint Trauma)
Authors: Birrer, Richard B.; Bordelon, R. Luke; Sammarco, G. James
------------------------------------------------------------------------------
Subjects: Ankle_Wounds and injuries
Sprains_Care and treatment
Wounds and injuries_Care and treatment
Reference #: A12045365
==============================================================================
Abstract: Ankles suffer many minor injuries that can become more serious if
treated improperly. A comprehensive diagnosis and treatment guide
provides information to prevent further injury.
==============================================================================
Press for more (? for help) ! scroll
Citation: Postgraduate Medicine, Jan 1991 v89 n1 p251(5)
------------------------------------------------------------------------------
Title: Ankle sprains are always more than 'just a sprain.' (includes
articles on ankle anatomy and rehabilitation of the sprained
ankle)
Authors: Stanley, Keith L.
------------------------------------------------------------------------------
Subjects: Ankle_Wounds and injuries
Sprains_Care and treatment
Reference #: A11898381
==============================================================================
Full Text COPYRIGHT McGraw-Hill Inc. 1991
When your patient sprains an ankle, you know what to do. The diagnosis is not
difficult, treatment is minimal, and the prognosis is excellent--right? Not
always. Reading Dr Stanley's article will help you diagnose, treat, and
rehabilitate with confidence.
Ankle sprains can occur under many circumstances, but they are most likely to
happen during participation in sports. Not surprisingly, ankle sprains are the
most frequent sports-related injury, accounting for an estimated 30% of all
such injuries (in basketball, an estimated 45% among men and 38% among
women).[1,2] Most ankle sprains are treated by primary care physicians.
Types of ankle injury
Lateral injuries to the ankle constitute about 90% of ankle sprains. These
usually occur when the ankle inverts and the foot supinates. External rotation
of the tibia may also occur. The most commonly involved structures include the
anterolateral capsule and the anterior talofibular, anterior tibiofibular, and
calcaneofibular ligaments (see Anatomy of the ankle).
Most injuries to the medial (deltoid) ligament involve pronation and eversion
of the ankle. There may also be a concomitant internal rotation of the tibia.
Most authorities agree that this type of injury constitutes less than 10% of
ankle sprains.[1]
In injuries that occur during high-energy stress to the ankle, the examiner
must always consider the possibility of related injury, such as injury to the
syndesmosis (rarely an isolated injury) as well as fracture. Fractures to look
for during examination of an ankle injury include avulsion fractures of the
malleoli or tarsal bones, epiphyseal fractures in young patients, and
fractures of the anterior process of the calcaneus or base of the fifth
metatarsal. The patient should also be evaluated for injury to the bifurcate
ligament.
Clinical evaluation
The mechanism of injury should be established during history taking. This
knowledge may aid in identifying injured structures and in determining the
force of the injury. The ambulatory status of the patient after the injury
should be ascertained.
Putting the patient in a comfortable position aids in examination of the
injured ankle. The active and passive range of motion of the injured ankle
should be observed. The uninvolved limb should always be evaluated to
determine the normal range of motion, muscle strength, and ligament laxity for
that patient. The location of any edema and ecchymosis should be noted, and
the vascular and neurologic status of the involved ankle should be assessed.
Palpation should begin away from the area of suspected injury. Palpation of
the forefoot, midfoot, and hindfoot structures is recommended before going on
to the ankle ligament structures. The base of the fifth metatarsal (the
insertion site of the peroneus brevis) should always be palpated, because it
is a common fracture site for inversion injuries of the ankle. The entire
course of the fibula as well as the syndesmosis should be palpated. This is
especially important with medial ligament injuries, since they are rarely
isolated and there is usually concomitant injury to the syndesmosis structures
or fibula (eg, Dupuytren's or Maisonneuve fractures).
The ligament structures, both medial and lateral, should be palpated next and
may be stressed to determine instability. Demonstration of a positive anterior
drawer sign (ability to sublux the talus anteriorly out of the ankle mortise)
is probably the most common clinical indicator of instability. The test should
be done with the foot in neutral and plantarflexed positions. The test for the
anterior drawer sign is done by stabilizing the tibia with one hand and
attempting to translate the talus anteriorly by force applied to the calcaneus
with the other hand.
Radiographic evaluation
Radiographic evaluation is a vital part of the examination of patients with a
sprained ankle, including those with only temporary ankle dysfunction. I
believe that all ankle sprains in skeletally immature patients should be
evaluated radiographically. X-ray films should be scrutinized to determine if
the ankle morten maintained. The types of fractures me
previously should be ruled out, as well as medial, lateral, or posterior
malleolar fractures.
The usefulness of adjunctive studies, such as stress roentgenography and
arthrography, is controversial[1,3-6] and should be left to specialists. These
studies as well as computed tomography (CT), magnetic resonance imaging, and
CT arthrography are beyond the scope of this article.
Grading ankle injury
Most physicians use a grading system of 1 through 3 to classify the severity
of ankle sprains. However, much debate about this system continues, especially
regarding differentiation between a severe grade 2 and a grade 3
injury.[1,4,6,7]
GRADE 1--Patients with this level of injury usually exhibit localized
tenderness (but no instability), normal range of motion, and little or no
functional disability.
GRADE 2--This level of injury has a wide range of symptoms. Moderate to severe
pain, edema and ecchymosis, and abnormal range of motion are common. Range of
motion may sometimes be severely impeded. There may or may not be instability
or pain during anterior drawer testing. Grade 2 injuries are characterized by
incomplete tearing of ligament fibers.
GRADE 3--This level of sprain is much more disabling than grade 2. There is a
marked deficit in range of motion, and ambulation is usually impossible.
Marked pain, edema, and hemorrhage are present. Complete disruption of the
ligament is usual.
Treatment
Treatment depends on the severity of injury. While controversy exists about
proper treatment of severe grade 2 and grade 3 injuries, most investigators
agree that nonsurgical treatment is appropriate in most cases.[1,2,4-8] There
is also debate on early mobilization versus immobilization. The literature
seems to indicate that, compared with immobilization, an early return to
athletics or work activity combined with early mobilization does not increase
the incidence of treatment failure.[9]
GENERAL MEASURES--Early treatment of ankle sprains includes protection, rest,
the application of ice and compression, and elevation. Ice may be applied by
ice pack, by placing the foot in a slush bucket or iced whirlpool, or by
cryotemp (Jobst Cryo Temp System) combined with compression provided by an
elastic support garment. Ice should be applied for 15 to 20 minutes during
every 1 to 2 waking hours, and this therapy should be continued for at least
72 hours. Contrast baths may then be initiated. Caution should be exercised to
avoid frostbite or nerve injuries during prolonged cryotherapy. Compression
may be accomplished through use of a felt or foam horseshoe pad applied with
an elastic wrap, splinting, air or gel stirrup braces, support garments, or
taping.
The typical emergency department treatment of applying an elastic bandage and
sending the patient home on crutches has little or no place in the care of
ankle sprains. The foot should not be held in an equinous position. If the
diagnosis is uncertain, a posterior splint or posterior sugar-tong splint may
be used to protect the ankle. These splints provide compression and protection
and still allow cryotherapy.
GRADE 1 SPRAINS--These injuries should be treated with ice and compression.
Motion should be restricted to prevent inversion or eversion. Nonsteroidal
anti-inflammatory drugs may be used, but their efficacy is not well
established except to speed improvement in functional capacity.[10]
Rehabilitation should begin on the first day after injury (see Rehabilitation
of the sprained ankle).
GRADE 2 SPRAINS--These injuries require an individualized treatment plan that
depends on the severity of injury and level of functional disability. Ice,
compression, and elevation are again appropriate.
How to protect the ankle and whether to use early mobilization or
immobilization must be decided for each patient. The literature supports early
mobilization.[1,2,7-9] If cast immobilization is used, it should be for a
short term (10 to 14 days) and followed by use of an ankle brace and
rehabilitation. A better alternative may be the use of a commercially
available cast-brace (tibial walker), which immobilizes the ankle for weight
bearing but allows removal of the device for physical therapy and
rehabilitative exercises.
GRADE 3 SPRAINS--Accurate diagnosis is of utmost importance in treatment of
grade 3 injuries. The controversy over surgical versus medical treatment is
still debated in the literature. Surgical treatment is outside the scope of
this article, but a published study by Brand and colleagues[3] is available
for review. Surgical intervention may be indicated if a diastasis of the
syndesmosis cannot be reduced or if the integrity of the ankle mortise cannot
be maintained with cast immobilization.
Some phns opt for 3 to 6 weeks of immobilization for patients with grade
3 ankle sprains. Another alternative would be 10 to 14 days of cast
immobilization, followed by application of a cast-brace and rehabilitation.
Cast-bracing may also be used initially to allow earlier physical therapy and
mobilization.
Physicians should realize that ankle sprains are significant injuries. They
can have serious sequelae or even cause disability if inadequately or
inappropriately treated. One cliche that should be deleted from physicians'
vocabularies is "it's just a sprain." Not all ankle sprains are identical.
Diagnosis, treatment, rehabilitation, and prognosis should be individualized
for each patient.
Anatomy of the ankle
The osseous structures usually involved in ankle sprains include the talus,
calcaneus, tibia, and fibula. The talus sits on the anterior two thirds of the
calcaneus in a mortise formed by the tibia and its medial malleolus and the
fibula and its lateral malleolus. Because the talus is wider anteriorly, the
ankle has greater osseous stability when in a neutral position (90%) or in
dorsiflexion.
The ligamentous anatomy may be divided into medial and lateral structures. The
medial ligaments, although collectively called the deltoid ligament, are
actually several different structures arranged in two groups: deep (anterior
and posterior tibiotalar) and superficial (tibionavicular and tibiocalcaneal).
The lateral ligaments include the anterior and posterior talofibular and the
calcaneofibular. The anterior talofibular ligament is taut in equinus
(plantar) flexion and inversion. The calcaneofibular ligament is not stressed
during inversion if the anterior talofibular ligament is intact, but it can be
stressed during inversion in dorsiflexion.
The syndesmotic ligaments must also be mentioned. These are currently
recognized as vital to ankle stability and, when injured, possibly the
greatest contributors to chronic ankle instability.[1,2] The syndesmotic
ligaments are the anterior and posterior tibiofibular, the inferior
transverse, and the interosseous.
References
[1]Balduini FC, Vegso JJ, Torg SS, et al. Management and rehabilitation of
ligamentous injuries to the ankle. Sports Med 1987;4(5):364-80 [2]Chapman MW.
Sprains of the ankle. In: American Academy of Orthopaedic Surgeons
instructional course lectures. Vol 24. St Louis: CV Mosby, 1975:294-308
Rehabilitation of the sprained ankle
Rehabilitation is the key to recovery from ankle sprains and should begin on
the first day after injury in most situations. The program must be customized
on the basis of the severity of injury and the patient's normal level of
activity.
Patients with grade 1 ankle sprains can begin a comprehensive rehabilitation
program on the day of the injury, including range-of-motion exercises,
stretching of the Achilles tendon, and isometrics or manual resistance
exercises (figure 1). Resistance exercises with a sport cord or surgical
tubing can be initiated early (figure 2). Double- and single-leg toe raises on
a flat surface, progressing to a step or incline board, should be included.
Proprioceptive training may be accomplished with exercises on a balance board
or balance beam or simply with single-leg standing with eyes closed. As
symptoms allow, exercise such as swimming or stationary bicycling may be
added, gradually progressing to straight-ahead jogging with no turns to stress
the ankle.
Depending on the athletic ability and expectations of the patient, the next
step in the program would be more stressful patterns of running. These
exercises should be done with either an ankle brace or ankle taping in place.
The patient's return to full activity is dependent on successful progression
through each step of the rehabilitation.
Grade 2 and grade 3 injuries require customized programs. Usually,
range-of-motion exercises can be safely done only in plantar flexion and
dorsiflexion early in the course of treatment. Stretching the Achilles tendon
by using a towel to help dorsiflex the foot can also be started early.
Isometrics or manual resistance exercises may be begun in the initial phase of
treatment. As range of motion and stability improve and symptoms of pain and
edema subside, resistance exercises with tubing, proprioceptive training,
swimming, and bicycling may be added.
If the patient is not progressing as expected or is having problems with the
rehabilitation program, then medically supervised physical therapy may be
indicated.
References
[1]Balduini FC, Vegso JJ, Torg JS, et al. Management and rehabilitation of
ligamentous injuries to the ankle. Sports Med 1987;4(5):364-80 [2]Vegso JJ,
Harmon LE 3d. tive management of athletic ankle injuriesn Sports
Med 1982;1(1):85-98 [3]Brand RL, Collins MD, Templeton T. Surgical repair of
ruptured lateral ankle ligaments. Am J Sports Med 1981;9(1):40-4 [4]Chapman
MW. Sprains of the ankle. In: American Academy of Orthopaedic Surgeons
instructional course lectures. Vol 24. St Louis: CV Mosby, 1975;294-308
[5]Drez D Jr, Young JC, Waldman D, et al. Nonoperative treatment of double
lateral ligament tears of the ankle. Am J Sports Med 1982;10(4):197-200 [6]Kay
DB. The sprained ankle: current therapy. Foot Ankle 1985;6(1):22-8 [7]Nemeth
VA, Thrasher E. Ankle sprains in athletes. Clin Sports Med 1983;2(1):217-24
[8]Linde F, Hvass I, Jurgensen U, et al. Early mobilizing treatment of ankle
sprains. Scand J Sports Sci 1986;8(2):71-4 [9]Wilkerson GB. Treatment of ankle
sprains with external compression and early mobilization. Phys Sportsmed
1985;13(6):83-90 [10]Dupont M, Beliveau P, Theriault G. The efficacy of
antiinflammatory medication in the treatment of the acutely sprained ankle. Am
J Sports Med 1987;15(1):41-5
Dr Keith L. Stanley, MD is a family physician trained in primary care sports
medicine, practicing in Tulsa, Oklahoma. He serves as team physician for the
University of Tulsa, Oral Roberts University, the Tulsa Drillers AA baseball
team, and Tulsa Union High School.
==============================================================================
Thanks to Tim Reyes for finding this article and sending in a
copy for inclusion in the GTC archives!
Citation: The American Journal of Sports Medicine, Jan-Feb 1994 v22 n1 p
78(5)
------------------------------------------------------------------------------
Title: Ankle sprain prophylaxis: an analysis of the stabilizing effects
of braces and tape.
Authors: Shapiro, Matthew S.; Kabo, J. Michael; Mitchell, Peter W.;
Loren, Gregory; Tsenter, Michael
------------------------------------------------------------------------------
Subjects: Ankle_Wounds and injuries
Sprains_Care and treatment
Orthopedic braces_Evaluation
Adhesive tape_Therapeutic use
Reference #: A14944008
==============================================================================
Author's Abstract COPYRIGHT American Orthopaedic Society for Sports Medicine
1994
ABSTRACT Five cadaveric ankles were used to determine the effects of
prophylactic bracing and tape on resisting an inversion moment applied to the
ankle. The ankles were tested in neutral flexion and 30 degrees of plantar
flexion and with both low- and high-top shoes. Eight different strap-on braces
were studied. High-top sneakers significantly increased the passive resistance
to inversion afforded by all braces and tape. Many of the braces functioned to
resist inversion at a level that was comparable with or exceeded the
capability of freshly applied tape. This finding was independent of the type
of footwear. Braces that were not as effective as freshly applied tape
nevertheless retained the advantage over tape in that they could be easily
readjusted and their effectiveness restored, whereas the quality of the
support provided with tape deteriorated with usage.
Full Text COPYRIGHT American Orthopaedic Society for Sports Medicine 1994
Ankle sprains are one of the most common injuries treated by orthopaedic
surgeons and athletic trainers. Garrick, [9] in an epidemiologic study of
ankle sprains, found that the lateral ligament complex is the single most
frequently injured anatomic structure in athletes, and that ankle sprains
account for 10% to 20% of the time lost from athletic participation. Jackson
et al. [14] reported that ankle sprains were the most common injury in a group
of military cadets participating in sports.
In most cases, ankle sprains occur as a result of inversion injury. This can
result from an athlete landing on his or her inverted foot or landing on an
opponent's foot or another obstacle. The degree of inversion is amplified by
the follow-through momentum of the body. This situation causes a moment about
the ankle joint, which further inverts the ankle. The ability of an athlete to
effectively fire his or her peroneal muscles may counter this inversion
tendency. If the moment is unchecked, inversion will continue until bony
apposition between the calcaneus and medial malleolus occurs. During this
process, the anterior talofibular and the calcaneofibular ligaments are
loaded, and frequently tear. More severe injuries may rupture the anterior
tibiofibular or deltoid ligaments as well. [5,15]
In an attempt to decrease the incidence of this common injury, physicians and
trainers have used ankle taping as a prophylactic measure. Several studies
have demonstrated the efficacy of ankle taping in terms of restricting motion
of the ankle, as well as decreasing the incidence of ankle sprains. [1,6,10]
Subsequent studies, however, have demonstrated that the effectiveness of ankle
taping decreases rapidly with exercise. Several different reports have
demonstrated a 12% to 50% decrease in the stabilizing effect of ankle tape
after as little as 10 minutes of exercise, [3,8,11,16,17,19] Because of these
disadvantages, as well as cost and time considerations, along with concurrent
improvements in ankle brace design, physicians and trainers have turned to
removable braces as an alternative for ankle injury prevention. [20,22]
Because braces can be reused, they are a much less expensive application.
Additionally, braces can be applied by the athlete, whereas tape must be
applied by a trainer or coach. The brace is easily retightened during use, as
opposed to tape, which must be removed and replaced to restore its
effectiveness. In light of these factors, braces can be expected to maintain
their effectiveness during the entire period of use; tape cannot.
Several studies have shown that braces restrict ankle range of motion as
effectively as tape, and do not lose this effect with exercise. [2, 3, 7, 12,
13, 18, 21] Other studies have also reported that these orthotic devices do
not adversely affect athletic performance. [4,12] Nearly all of these studies
concentrated on evaluating the effectiveness of a particular brace with
respect to the performance of tape, or performed subjective user evaluations.
To date, no study has measured the passive mechanical effectiveness of these
devices. The effect of footwear on the effectiveness of braces has also been
addressed, but the results have been conflicting. Garrick and Requa [10] found
that high-top sneakers reduced the incidence of ankle sprains when compared
with low-top sneakers, but Rovere et al. [21] claimed that low-top sneakers
were better.
The present study addresses these conflicting stabilization issues from a new
perspective. The purpose of this study was to determine the passive mechanical
effectiveness of braces or tape and footwear in resisting ankle inversion. We
designed a system to measure the stiffness added by any combination of brace
or tape and shoe to a cadaveric ankle/foot preparation. In this way we were
able to measure the relative effects of taping and a variety of braces on the
tendency of an ankle to undergo an inversion angulation when loaded. In
addition, we examined the effect of high- or low-top sneakers on the efficacy
of each tape or brace preparation.
MATERIALS AND METHODS
Five male cadaveric ankles between the ages of 20 and 65 years were obtained
from the UCLA willed body program. A physical examination was performed on
each ankle and included an anterior drawer test and tibial talar shift test.
All ankles were radiographically normal. The ankles were prepared for testing
by transecting the tibia and fibula at midshaft and embedding the end of the
bones in a methylmethacrylate cylinder that could be rigidly mounted in the
testing device. The foot was transected at the tarsometatarsal junction. Three
or four 3/16 inch (or greater) diameter Steinmann pins were inserted anterior
to posterior through the calcaneus, and the ends of the pins were embedded in
a methylmethacrylate block that could be rigidly clamped to the footplate
fixturing device.
Taping was done in a standard fashion, using a thin foam underwrap and 2-inch
cloth adhesive tape in a standard figure-8 technique as is commonly employed
in the UCLA Athletic Training Center. Eight commercially available braces were
tested. These were obtained at no cost to the study from the manufacturers.
The braces tested were McDavid Ankle-Guard, A-101 (McDavid, Inc., Clarendon
Hills, IL), Air-Stirrup Ankle Training Brace (Aircast, Inc., Summit, NJ),
Gelcast (Centec Orthopaedics, Division of Royce Medical Company, Agoura Hills,
CA), Super-8 (Pro Orthopaedic Devices, Inc., Tucson, AZ), DonJoy Model FG-062
(DonJoy, Inc., Division of Smith & Nephew, Carlsbad, CA), Eclipse Excel Ankle
Support (Surefit Orthopaedics, Culver City, CA), Ankle Stabilizer (Cramer Gardne
r, KS), and High Top Ankle Support (Technol Products,
Inc., Fort Worth, TX). Braces were applied according to the manufacturer's
instructions. When a lace-up brace was applied, each lace was tightened
sequentially using a scale under tension to 20 pounds. VELCRO straps (VELCRO
USA, Inc., Manchester, NH), when present, were similarly tightened to 10
pounds before being attached.
Each ankle was tested in neutral dorsiflexion without tape or brace in a
standard low- and high-top sneaker. The laces of each sneaker were tightened
in the controlled manner previously described. Each ankle/brace or ankle/tape
preparation was then tested with both types of footwear in an identical
manner. Two repetitions were made for each possible combination with each
ankle. When tape was used, it was replaced for each new footwear application.
To simulate the position of the foot in plantar flexion, a 30 degrees wedge
block was placed under the heel of each sneaker. All tests were repeated for
each possible configuration for each ankle.
The testing device consisted of a footplate mounted on a laterally directed
roller bearing (Fig. 1). The tibial potting was attached to the axial load
cell connected to the fixed cross-member of the MTS-812 materials testing
machine (Materials Test Systems, Minneapolis, MN). The foot and shoe assembly
was positioned on the footplate and locked into place by clamping the plastic
embedded ends of the Steinmann pins directly to the plate. The plate rested on
an axle with two 4-inch diameter wheels. During vertical motion of the MTS
piston, the wheels were guided horizontally along a set of parallel rails. The
foot and plate assembly was free to rotate about the axis of the tibia. Axial
motion of the piston was always initiated with a slight compressive preload
causing the ankle to start from a position of a few degrees of inversion. This
configuration applies a pure force compressive couple that acts through the
wheel axis and the tibial shaft. Slight inversion with a preload ensures a
stable test configuration.
Force was recorded by the load cell mounted on the crossbar, horizontal
displacement was recorded for the w,heel axis with a potentiometer in a
voltage divider circuit, and inversion angle was recorded directly with an
inclinometer attached to the underside of the footplate. Axial (vertical)
displacement was at the rate of 2 cm/min. Ankle inversion was continued until
40 degrees was reached, at which time the piston motion was reversed and the
ankle unloaded. This value was selected to prevent damage to the ligamentous
structures of the ankle. Inversion moment was readily calculated from the
product of the horizontal displacement and the axial load.
The slow loading rate was intended to minimize the viscoelastic response of
the soft tissues so that the effects of our experimental variables could be
determined. Dynamic loadings, which are typically associated with ankle
sprains, would tend to increase the rigidity of the entire system independent
of the brace and footwear.
The sequence of testing each brace or tape construction was performed in the
following order: 1) neutral flexion, low-top shoe; 2) plantar flexlon, low-top
shoe; 3) neutral flexion, high-top shoe; and 4) plantar flexlon, high-top
shoe. The use of a particular brace or tape was randomized. The control state
using a low-top shoe was performed first and repeated again when all other
configurations had been exhausted. Comparison of the initial and final control
state measurements revealed no significant differences and provided direct
confirmation of the preservation of intact joint stability throughout the
tests.
Inversion force, moment, and stiffness (slope of the moment versus angle
curve) were determined for each possible combination of parameters. Regardless
of the measure used, the same general trends were seen in relation to type of
ankle support, type of shoe, and degree of plantar flexlon. Therefore, the
results presented will be restricted to the magnitude of the inversion moment
required to invert the ankle 30 degrees. This angle was selected because the
moment versus inversion angle curves were quite linear (average [R.sup.2] =
0.94) over a large range, indicating a very stable moment angle relationship.
For each foot the inversion moment value at 30 degrees of inversion was
divided by the corresponding average value from the baseline control of bare
foot plus low-top sneaker plus flat configuration on footplate. This
configuration for each foot was selected as the control state for the other
test configurations for the same foot.
To evaluate the braces in relation to the standard that is represented by
ankle taping, the percent change sion moment relative to the taped
condied as
([IM.sub.brace]-[IM.sub.tape IM is the value of the inversion moment obtained fo
r 30 degrees of ankle
inversion.
Mixed-model analysis of variance and t-tests were used to determine
significant differences.
RESULTS
The data are preferentially presented as ratios obtained by dividing the test
data by the average of the values of all of the ankle specimens for a selected
control state. This is preferable to simple percentage changes because
standard deviations can also be presented, which reflects the variation in the
data. For those interested, the percentage change from the control state is
readily obtained from the simple calculation: (ratio - 1) X 100 = percent. In
any event, larger numbers signify a greater difference from the control state.
A summary of the averages of the normalized ratios is presented in Table 1.
Figure 2 depicts the change in the normalized inversion moment ratio as a
function of the ankle test condition (neutral or plantar flexion, low- or
high-top shoe) for the taped ankles and a representative brace. Figure 3
displays inversion moment ratio for the different braces and tape for the
ankle test configuration (neutral flexion, high-top shoe) where the greatest
resistance to inversion was found. It can be readily seen that all braces and
tape were effective in increasing the resistance of the ankles to an inversion
moment. The use of high-top footwear maximizes the protective capability of
the prophylaxis. In all cases, greater force was required to invert the ankles
at 30 degrees when the foot was placed flat.
Figure 4 presents these changes as a function of brace type for both the low-
and high-top footwear for the case of no plantar flexion. The control state is
the foot plus low-top shoe only. All braces and tape significantly (P < 0.05)
stiffened the unprotected ankle in a low-top shoe. The stiffness observed with
the taped ankles represents the highest values possible, as previous studies
have verified that the effectiveness of tape decreases with use.
A greater inversion moment was required with the foot in a flat position than
when in plantar flexion for all configurations except for the unprotected
ankle. Braces and tape, therefore, are more effective in resisting ankle
inversion when the ankle is flat.
For the low-top shoe, flat configuration, all braces and tape provided a more
than two times improvement in the resistance to inversion. This improvement
was significantly higher only for the Super-8 brace design in this
configuration (P < 0.05). As seen for the control state, high-top footwear
provided a doubling of the resistance to inversion, regardless of whether the
ankle was in neutral position or in plantar flexion. Only for the neutral
position was this finding significant (P < 0.001).
In the high-top shoe, flat configuration, while there was considerable
variability, none of the braces were significantly different from tape. The
resistance of the Cramer brace design was less than or equal to the
performance of the taped ankle under all conditions studied, but these
differences were not significant. We caution against a negative interpretation
of this particular result because tape will always loosen and braces maintain
the advantage of a quick retightening.
The DonJoy, Aircast, Gelcast, and tape systems provided a substantial increase
in inversion resistance with high-top footwear for both the neutral and
plantar flexion positions.
DISCUSSION
Prophylaxis of ankle sprains is achieved by diminishing the tendency of the
ankle to undergo inversion. This has always been achieved by stiffening the
ankle joint by application of an external device. Taping with cloth adhesive
tape is still regarded by many sports physicians, coaches, and athletic
trainers as the standard application for the prevention of ankle sprains.
Ankle braces are regarded by some as a less costly way to perform the same
task. Still others claim that braces have distinct advantages over tape.
Whichever device is used, it shares the applied moment with the ankle and
achieves a stiffness that is higher than the ankle alone provides. Stiffness
can also be added by the sneaker that is worn in conjunction with the
prophylactic device. To put it simply, the stiffer the ankle/brace/sneaker
combination is, the less the resultant angulation for a given load.
Additional mechanisms for the function of prophylactic devices are possible.
An external device on the skin may increase the player's proprioception,
causing more effective muscular control. [11] This effect may be a benefit of
high-top sneakers as well. It is also possible that prophylactic devices
prevent the player from landing on an inv the unweighted
foot in neutrgus alignment. Once the foot has a certain degree of
inversion, however, the applied load (such as body weight) will cause an
inversion moment that must be resisted by the inherent stability of the ankle
and any external devices being worn. A stiffer ankle construction will have
less tendency for inversion-induced injury.
Sprains occur clinically in both dorsiflexion and plantar flexion. In certain
situations, only one of the two lateral ligaments is injured. Sprains that
preferentially injure the anterior talofibular ligament probably occur in more
plantar flexion. This position may be associated with injuries that occur when
the player lands on someone else's foot or on uneven ground. With the foot in
more plantar flexion, the distance between the center of rotation (the
tibiotalar joint) and the point of force application (the plantarflexed foot)
is greater; therefore, the inversion moment is correspondingly greater. Thus,
plantar flexion may be a more vulnerable position for ankle sprains. All of
the braces used in this study demonstrated decreased efficacy in plantar
flexion. The magnitude of this decrease was brace- and footwear-dependent.
The effect of a high-top sneaker was to improve the efficacy of the brace or
tape. In all cases, the presence of a high-top shoe required greater force to
invert the ankle. A two-times improvement was observed for an unbraced or
untaped ankle; when brace or tape was added, the benefit of using a high-top
shoe increased further. All braces demonstrated greater than two-times
improvement when used with the low-top shoe, which is comparable with the
improvement afforded to using a high-top shoe without a brace.
Because this was a cadaveric study, the dynamic effects of the stabilizing
muscles cannot be incorporated. Thus, we are able to report only the intrinsic
passive stability provided by these devices. We also are unable to evaluate
the subjective comfort of the devices and therefore cannot comment on the
issue of patient compliance.
CONCLUSIONS
The use of ankle braces and tape affords a dramatic increase in the protection
of the ankle by decreasing the resultant inversion caused by an applied force.
High-top sneakers significantly increase the passive resistance to inversion
afforded by all braces and tape. This effect was smallest for the Cramer
brace. Many of the braces function to resist inversion at a level that is
comparable with or exceeds the capability of freshly applied tape. This
finding was essentially independent of the type of footwear tested. Those
braces that were not as effective as freshly applied tape retain the advantage
over tape in that they can be easily readjusted and their effectiveness
restored, whereas the quality of the support provided with tape deteriorates
with usage. These braces represent good alternative choices for athletes who
refuse to wear high-top sneakers.
ACKNOWLEDGMENTS
The authors thank all of the brace manufacturers who contributed orthoses for
use in this investigation. The authors also acknowledge the assistance of Jim
Zachazewski, PT, ATC, in the implementation and instruction of the proper
ankle taping technique.
REFERENCES
1. Abdenour TEE, Saville WA, White RC, et al: The effect of ankle taping upon
torque and range of motion. Ath Training 14: 227-228, 1979
2. Beynnon BD, Renstrom P: The effect of bracing and taping in sports. Ann
Chir Gynecol 80: 230-238, 1991
3. Bunch RP, Bednarski K, Holland D, et al: Ankle joint support: A comparison
of reusable lace-on braces with taping and wrapping. Physician Sportsmed
13(5): 59-62, 1985
4. Burks RT, Bean BG, Marcus R, et al: Analysis of athletic performance with
prophylactic ankle devices. Am J Sports Med 19: 104-106, 1991
5. Colville MR, Marder RA, Boyle JJ, et al: Strain measurement in lateral
ankle ligaments. Am J Sports Med 18: 196-200, 1990
6. Delacerda FG: Effect of underwrap conditions on the supportive
effectiveness of ankle strapping with tape. J Sports Med 18: 77-81, 1978
7. Friden T, Zatterstrom R, Lindstrand A, et al: A stabilometric technique for
evaluation of lower limb instabilities. Am J Sports Med 17:118-122 1989
8. Fumich RM, Ellison AE, Guerin GJ, et al: The measured effect of taping on
combined foot and ankle motion before and after exercise. Am J Sports
Med 9: 165-170, 1981
9. Garrick JG :The frequency of injury, mechanism of injury, and epidemiology
of ankle sprains. Am J Sports Med 5: 241-242, 1977
10. Garrick JG, Requa RK: Role of external support in the prevention of ankle
sprains. Med Sci Sports 5: 200-203, 1973
11. Glick JM, Gordon RB, Nishimoto D: The prevention and treatment of ankle
injuries. Am J Sports Med 4:136-141, 1976
12. Greene TA, Hillman SKsupport provided by a semirigid
orthosis and adhesive ankle taping before, during, and after exercise. Am J
Sports Med 18: 498-506, 1990
13. Gross MT, Bradshaw MK, Ventry LC, et al: Comparison of support provided by
ankle taping and semi rigid orthosis. J Orthop Sports Phys Ther 9: 33-39, 1987
14. Jackson DW, Ashley RL, Powell JW: Ankle sprains in young athletes.
Relation of severity and disability. Clin Orthop 101:201-215, 1974
15. Johnson EJ, Markolf KL: The contribution of the anterior talofibular
ligament to ankle laxity. J Bone Joint Surg 65A: 81-88, 1983
16. Laughman RK, Carr TA, Chao EY, et al: Three-dimensional kinematics of the
taped ankle before and after exercise. Am J Sports Med 8: 425-431, 1980
17. Malina RM, Plagenz LB, Rarick GL: Effect of exercise upon the measurable
supporting strength of cloth and tape ankle wraps. Res Q 34: 158-165, 1963
18. Myburgh KH, Vaughan CL, Isaacs SK: The effects of ankle guards and taping
on joint motion before, during, and after a squash match. Am J Sports Med 12:
441-446, 1984
19. Rarick GL, Bigley G, Karst R, et al: The measurable support of the ankle
joint by conventional methods of taping. J Bone Joint Surg 44A: 1183-1190,
1962
20. Renstrom P: Sports traumatology today. A review of common current sports
injury problems. Ann Chir Gynecol 80: 81-93, 1991
21. Rovere GD, Clarke TJ, Yates CS, et al: Retrospective comparison of taping
and ankle stabilizers in preventing ankle injuries. Am J Sports Med 16:
228-233, 1988
22. Tropp H, Askling C, Gillquist J: Prevention of ankle sprains. Am J Sports
Med 13: 259-262, 1985
[TABULAR DATA OMITTED]
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Press for more (? for help) ! scroll
Citation: Physical Therapy, Jan 1994 v74 n1 p17(15)
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Title: Local sensation changes and altered hip muscle function following
severe ankle sprain. (includes commentary and author response)
Authors: Bullock-Saxton, Joanne E.; Leonard, Charles T.
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Subjects: Ankle_Dislocation
Hip_Muscles
Sprains_Physiological aspects
Muscle strength_Measurement
Reference #: A14737290
==============================================================================
Author's Abstract COPYRIGHT American Physical Therapy Association Inc. 1994
Background and Purpose. Changes in sensory information have been shown to
influence muscle function locally. Some clinicians, however, believe that the
influence may be more extensive. To investigate this clinical concept,
subjects with severe ankle sprain were assessed for local sensation changes
and proximal hip/ back muscle function. Subjects. Of a total of 361 potential
subjects whose medical histories were assessed, 20 men (age 18-35 years) who
had previously sustained a severe unilateral ankle sprain and 11 matched
"control" subjects with no previous lower-limb injury participated in the
study. Methods. Using this experimental model, ten of vibration vibration in
the ankle (indicating sensation changes) as well as surface electromyography
of muscle recruitment patterns for hip extension (indicating muscle function
proximally) of the biceps femoris, gluteus maximus, and lumbar erector spinae
muscles were made on both sides of the unilaterally injured and matched
control subjects. Results.Significant decreases in vibration perception and
significant delays in gluteus maximus muscle recruitment during hip extension
were found in the injured group. Conclusion and Discussion. The author
concludes that both local sensory and proximal muscle function changes are
associated with unilateral severe ankle sprain.
Full Text COPYRIGHT American Physical Therapy Association Inc. 1994
Key Words: Ankle; Electromyography; Hip; Muscle performance, lower extremely;
Sensation; Sprains and strains.
The existence of a complicated feedback system between muscles and joints and
the central nervous system is well recognized. Interference with sensory
feedback may affect a person's ability to monitor movements or to make
appropriate adaptations and adjustments to movement. For example, a change in
postural stability when a person stands on one leg following ankle sprain was
attributed by Freeman[1] to altered proprioceptive input from the ankle joint
and its influence on the postural control of the muscles.
This relationship between joint receptor information and muscle function has
interested researchers for some years, and the relationships between
stimulation of joint afferents and muscle activity have been demonstrated in
both animal and human studies.[2-5] For example, Ekholm et al[2] investigated
the response to various articular stimuli of decerebrate and, in some
instances, spinalized cats. They found that increasing the articular pressure
in the knee joint, as well as pinching its capsule, led to decreased
quadriceps femoris muscle (ie, extensor) activity, whereas pinching the knee
capsule elicited an increased response from the knee flexors (biceps femoris
muscles). In their study of human subjects, Stokes and Young[3] considered
that joint injury can decrease the activity of muscles, leading to weakness
and wasting. They measured the rectified integrated electromyographic (EMG)
activity of both quadriceps femoris muscles of patients who had a meniscectomy
or an arthrotomy and recorded large decreases (80%) in quadriceps femoris
muscle activity on the side of surgery. This effect persisted for up to 15
days postoperatively 30%-40%), despite the lack of pain at that time.
A possible mechanism for this decreased activity might be the excitation of
joint afferents in the capsule because of pressure caused by joint infusion.
Indeed, in 1965, De Andrade et al[4] showed that in healthy human subjects and
in those with pathology, infusion of saline into the knee joint was
responsible for decreased activity of the quadriceps femoris muscles. Results
of recent studies by Iles et al[5] have indicated that as the volume of saline
infused into the human knee joint is increased, the amplitude of the H-reflex
is decreased and that even apparently imperceptible volumes of saline could
decrease quadriceps femoris muscle activity. In these studies, the decrease of
extensor activity following afferent stimulation was highlighted.
The relationship between ankle articular mechanoreceptor function and the
reflex activity in the limb of the cat was also investigated by Freeman and
Wyke.[6] Establishing the normal reflex muscular response of the tibialis
anterior and gastrocnemius muscles, these researchers decreased the afferent
information from the joint by local anesthesia and by electrocoagulation of
the articular tissues. Both procedures caused an abolition of the normal
reflex muscular response to movement, indicating the importance of articular
information to regulation of muscle activity. Freeman and Wyke[6] believe that
muscle activity is regulated through the contribution of the articular
impulses to a facilitatory bias to the gamma motoneurons of the muscle
spindles. If such an influence exists, then their early assertion that
articular afferents influence local muscle activity is correct and has been
supported by the later research of Iles et al.[5]
This experimental evrts the clinical observation that a joint
injury involving sensory receptors can influence the muscle function about
that joint. However, a more complex relationship than this has also been
proposed. This proposed relationship is that altered sensation in one joint
could lead to muscle function changes in another more proximal joint. This
concept has been the basis of teaching by Lewit[7] and Janda[8] for several
decades. Some experimental data on cats do exist demonstrating that the motor
system has a tendency to extend dysfunction into a larger area.[9]
Although difficult to extrapolate results from animal studies to human
behavior, Wyke[9] observed that in the cat, an injury of the joint capsule or
ligaments influences muscle activity not only in muscles that cross the
injured joint, but also in remote muscles. Wyke stated that
... interruption of the flow of impulses
from the mechano-receptors in a joint
capsule into the central nervous system
should result in clinically evident disturbances
of perception of joint position
and movement and of the reflexes
concerned with posture and gait.[9](p44)
Thus, the arthrokinetic reflex might be considered as a triggering factor that
would initiate a whole chain of adaptation reactions, eventually resulting in
a changed movement pattern. The possibility that sensory deficits associated
with localized injury in one part of the body influence muscle function in
another and may ultimately lead to pain has considerable implications for the
physical therapist, influencing both the preventive and therapeutic approaches
to patient care.
Wyke[9] also argued that articular sensory information is vital to normal
postural reflexes. He cited observations of impaired postural reflex activity
of muscles following severe ankle sprain of humans and proposed that this
might be a reflection of the impaired proprioceptive information from the
damaged mechanoreceptors. As afferent impulses travel to cerebellar and
cortical centers,[10] the impaired afferent information from the ankle joint
may be sufficient to impair the motor regulation of body posture. In their
experimental study of postural stability following ankle sprain, Tropp et
al[11] found a significant decrease in postural stability when compared with
noninjured subjects, thus confirming Wykes'[9] observations. Recent
experiments by Gauffin and colleagues[12] have indicated that patients with
unilateral anterior cruciate ligament injury demonstrated bilateral
alterations in their postural control when compared with uninjured subjects.
They postulated that these alterations may be due to "central adjustments of
motor control." The postulation that changes in sensory input could cause
alterations in the function of muscles in a joint remote from the injury seems
to be well justified, although no direct experimental evidence of this in
humans has yet been reported.
This study was conducted, therefore, to investigate whether a localized lesion
at a peripheral joint such as the ankle influenced the sensation in that area
as well as the muscle function in more proximal regions such as the hip and
pelvis and, if so, whether such changes were interrelated. The sensory and
muscle function in both limbs of subjects who had previously sustained a
severe unilateral ankle sprain was compared with that in both limbs of
noninjured ("control") subjects.
For this study, appropriate tests of sensory and muscle function needed to be
selected. Freeman et al[13] theorized that ankle instability following injury
develops primarily due to lesions of mechanoreceptors in the joint capsule and
ligaments. This instability impairs both the static position and joint
movement sense. This theory was not supported by Gross,[14] who compared
active and passive joint position sense in both injured and uninjured subjects
and found no significant difference between them. However, the method of
testing used for assessing joint position sense involved strapping the foot to
a movable footplate with firm pressure. It is possible that mechanoreceptors
on both plantar and dorsal surfaces of the foot, which were not compromised by
the lateral ligament ankle injury, were able to provide sufficient cues for
the subject to determine ankle joint position. Barrack and colleagues[15]
appear to have developed a successful measurement procedure for eliminating
pressure cues during testing of joint position sense of the knee following
anterior cruciate ligament injury. These researchers found significant
deficits in joint position sense of the knee.
If damage to sensory receptors from severe ankle joint sprain is to be
accurately measured, a test that is sensitive to changes in sensory receptos nee
ded. Two factors were considered ingard: (1) the
influence of joint stress on discharge rates of mechanoreceptors and (2) the
effects of age on sensation. Wyke,[9] in his description of three types of
articular nerves, outlined how the frequently occurring group II nerve fibers
terminated onto both low-threshold, slowly adapting mechanoreceptors (type 1)
and low-threshold, rapidly adapting mechanoreceptors (type II). The type I
mechanoreceptors, found in clusters around the joint capsule, where the
greatest degrees of stress during movement are likely to occur, are sensitive
to changes in joint pressure and position. Their rate of discharge adapts
rapidly to the degree of joint stress. It is likely that capsular tears,
rupture of small nerve fibers, and joint edema following ankle sprain could
cause alterations of discharge from these receptors, as indicated by Freeman
et al.[13]
In persons without joint injuries, perception of some superficial and deep
sensations decreases with age. These sensations include tactile, two-point
discrimination; vibration perception; and joint movement sense.[13] Such an
age-related decline suggests that these sensory modalities are vulnerable to
change. Vibration perception requires information from both superficial and
deep mechanoreceptors as well as a functional cortical sensory association
area.[16] Testing vibration perception, therefore, would provide information
on the integrity of sensory receptors possibly damaged due to ankle
ligamentous injury. This assessment of sensation is capable of a high degree
of control in comparison with current tests used for assessing tactile,
two-point discrimination or joint movement sense around the ankle. For these
reasons, vibration perception was chosen as the variable for assessment of
sensory function in this study.
Muscle function in each limb was investigated in terms of the temporal
sequence of activation (as illustrated in EMG signals) of the gluteus maximus,
hamstring, and ipsilateral and contralateral lumbar erector spinae muscles
during the movement of hip extension from a prone-lying position. Janda[17]
has claimed that the determination of the order of activation of muscles
performing a simple movement is important for the understanding of the methods
used by patients to move their body and that this knowledge helps to reveal
the area of impairment. Hip extension was selected for this study, not only
because the studied muscles were separated from the site of injury but also
because of its functional importance in stance and locomotion. Due to the
complexities of the gait process, it was considered advisable to isolate the
hip extension motion rather than to study muscle function during gait. Much
greater control could be imposed experimentally by assessing muscle activation
during hip extension from a prone-lying position than would be possible during
locomotion.
In my study, the effects of ankle sprain (the independent variable) on
vibration perception at the ankle and the pattern of activation of specified
muscles around the hip and low back (the dependant variables) were measured. A
matched control group was used for comparison. Only subjects who had sustained
a unilateral ankle sprain were included in the injured group, so that
side-to-side differences between their injured and uninjured sides could be
compared with the normal side-to-side differences demonstrated in the
uninjured control group.
Method and Materials
Subjects
Two groups of subjects were studied: an "injured" group, who had previously
sustained a severe unilateral ankle sprain, and a matched "control" group, who
had no previous lowerlimb injury. To control variables between the two groups
of subjects, a suitable population of sufficient size was sought. The armed
forces provided such a source. The Australian Defence Force (Army) gave
permission for their soldiers and officers to volunteer to be subjects for
this study.
For the injured group, subjects were included if they had previously sustained
a grade II+ or III (severe or unstable[18]) lateral ankle sprain that was
significant enough to have caused marked swelling at the time of injury and
discomfort while walking. Treatment must have included a period of
immobilization. The subjects' right side must also have been the preferred (or
"skill") side. Subjects were excluded if they had had a significant injury to
any other lower-limb joint or a significant injury to either leg. Of
particular concern was the need to exclude subjects who may have had a history
of incoordination or clumsiness (operationally defined as a history of sensory
and/or motor dysfunction not related to injury, in the absence of intellectual
impairmas essential to ensure that an existing neurological deficit
was not a predisposing cause of the ankle sprain, because the finding of
differences in localized sensory function in the control group could then be
said to be a cause, rather than an aftereffect, of the injury.
I assessed the medical histories of 361 potential subjects; 80 subjects (22%)
were found to have sustained an ankle sprain on both sides, and 233 subjects
(65%) either had injuries in other joints or were unavailable to participate
in the study. Sixty-four men (18%) underwent the detailed screening process,
but only 20 (6%) of these subjects met all inclusion criteria.
Variables measured were age, physical characteristics such as height and
weight, and level of physical activity (eg, during sports and work). Subjects
for the control group, who matched subjects in the injured group in these
characteristics, were sought from the same army units. Eleven men fitting the
criteria were found. Table 1 illustrates the distribution of relevant
variables between the two groups.
[TABULAR DATA OMITTED]
Measurement
Vibration perception. Dyck et al[19] have discussed the problems associated
with the measurement of the threshold of vibration perception and the
inadequacy of current clinical methods (such as the use of tuning forks) in
providing reliable, repeatable results. For my measurements of vibration
sensitivity, it was desirable to ensure that frequency and amplitude of
vibration could be varied, a consistent pressure of application could be
maintained, and the subject could remain alert and cooperative. To meet the
first of these criteria, a mechanical oscillator(*) connected to a Power
oscillator(dagger) was used. This instrument allowed variation of both
frequency and voltage and provided measures of output voltage directly related
to acceleration (force intensity) of the oscillator head at each of the chosen
frequencies. To ensure a constant pressure of this device on the skin, the
oscillator was suspended from one end of a system of pulleys and a mass of
equal weight was suspended from the other end as a counterbalance.
The subject was positioned side lying with the leg to be tested uppermost and
secured in a lower-leg rigid support (back slab) to control the degree of
ankle dorsiflexion, and supported on a high-density foam cushion Fig. 1). The
oscillator was positioned perpendicular to and just touching a point on the
inferior fibular head, and the weight on the counterbalance was reduced by 50
g. The head of the oscillator, therefore, made contact with the fibular head
with a gravity-applied force of 50 g. The voltmeter, which reflected the
amplitude of oscillation of the vibrator, indicated both when vibration was
occurring and when it had ceased.
Because there appears to have been little research into the perception of
vibration at different frequencies, a range of frequencies (ie, 100, 150, 200,
and 250 Hz) was assessed. For each frequency, the oscillator amplitude (which
could be termed "vibration strength") was slowly increased until the subject
stated that he perceived vibration. This voltage was recorded as the
threshold. Two measurements at each frequency were taken on one limb to
provide an estimate of measurement error, before commencing the series on the
second limb. The order of presentation of the series of frequencies to each
subject and between subject sides was randomized. One researcher (JEB-S)
tested all subjects.
To determine the consistency of subject threshold to vibration perception, a
repeatability test was carried out prior to the major study. Ten repetitions
at each frequency on one limb were chosen randomly from a subset of the sample
composed of five injured group subjects and five control group subjects. The
repetitions of each frequency were taken within a 1-hour time span with a
30-second interval between repetitions. The confidence interval limits of the
means (mean[+ or -] t x standard error) and their standard deviations of the
within-subject - between-replication" variation (derived from a suitable
analysis of variance) for each frequency were comparable for each group and
are listed in Table 2. These results indicated that for uninjured subjects and
for those with previous ankle injury, the threshold of vibration perception at
each frequency was repeatable on the one day.
[TABULAR DATA OMITTED]
Muscle activation. Surface EMG was used to provide information regarding the
activation of the specified muscles during hip extension, utilizing bipolar
surface electrodes (silver-silver chloride) on each of the ipsilateral and
contralateral lumbar erector spinae, gluteus maximus, and hamstring muscles of
both limbs. With subjects positionedg, EMG sites were identified,
and electrre placed 10 mm (0.39 in) apart on each prepared site. The
electrodes were positioned parallel to the line of the muscle bellies and over
the area of greatest muscle bulk, determined after a resisted contraction of
the specific muscle. Lumbar erector spinae muscles were monitored adjacent to
the intervertebral level of L2-3, the upper fibers of the gluteus maximus
muscle were monitored, and electrodes were placed on the hamstring muscles
over the biceps femoris muscle. For each hip extension motion, signals from
the four muscle groups were preamplified using a Medelec PA65
preamplifier(double dagger) before passing to a Medelec AAM63
amplifier/filter.(double dagger) The signals were sampled at a rate of
2,500.Hz, were bandpass filtered at a lower frequency of 0.8 Hz and a higher
frequency of 800 Hz, and were recorded on an eight-channel ink jet chart
recorder(section) for monitoring of the signal during data collection. The EMG
signals were also passed to an analogue-to-digital converter in a computer and
stored for analysis.
The starting position of each leg was traced onto a sheet of paper placed over
the base of the test bed to ensure a consistency of position. A feedback
system was devised to assist the subject in controlling his own range of
motion. An inclinometer(parallel) provided a recording of the motion of the
limb during hip extension. The inclinometer was connected to an oscilloscope
positioned below a face hole in the test bed to be monitored by the subject.
The inclinometer produced an output in the form of a moving line on the
oscilloscope, and an initial zero "base" line (representing the limb in
neutral) and a "target" line (representing the designated 15[degrees] range of
hip extension) were marked. Thus, the subject had feedback for the position of
his limb as he moved the limb through the range of motion.
The inclinometer, fixed to a curved metal plate, was strapped to the lateral
side of the thigh on a line between the greater trochanter and the lateral
femoral condyle with the femur in a horizontal position, so leading to zero
output of the inclinometer (giving the base line). Passive limb movement to
the edge of a 15-degree template allowed the 15-degree target line trace to be
recorded on the oscilloscope. When the subject moved his limb, a third
(moving) line provided feedback of the limb's position in relation to the
target line. By connecting the inclinometer to the chart recorder and
computer, the position of the limb was recorded at rest and during movement.
Speed of motion was controlled by the subject moving the limb through the
15-degree range of motion at a rate equal to three beats of a metronome set at
72 beats per minute. That is, the limb moved through a 6-degree arc of motion
per second, which was considered to be approximately equal to a slow walking
speed.
Subjects were encouraged to relax prior to the hip extension, the chart
recording indicating whether the muscles were at rest. Only then was the trial
commenced, with EMG signals being recorded for a count of three beats of the
metronome prior to the request to extend the hip. This initial "at rest"
recording not only provided a base line signal prior to hip extension, but
also allowed the EMG recording of any activity within the muscle as the
subject prepared to move into hip extension. An initial training period
ensured that the subject understood what was required of him. For each
subject, a 10-second recording of EMG and inclinometer signals was made during
each of the six tests on each side. A 10-minute interval separated the tests
on the two sides to allow recovery from any possible fatigue. The same
researcher carried out all testing.
For analysis of EMG data, the order of muscle activation represents the
sequence of each muscle's entry into a coordinated muscle activity. Visual
observation is the method usually used by researchers for this determination.
For this study, however, it was important for statistical purposes to find a
quantitative measure that would allow comparison between groups of subjects of
the relative behavior of muscles contributing to a group activity.
Because one or more muscles might contract prior to the commencement of hip
extension and the starting point of individual muscle contractions relative to
hip motion might vary, a consistent reference point for comparison purposes
was needed. Therefore, the commencement of hip movement (H) was taken as a
reference. The temporal measure used to recognize this was the time span (in
seconds) between onset of individual muscle activity (O) and commencement of
hip movement (H), as determined by the inclinometer (ie, O-H).
Calculation of the time span between points of onset of the fth
muscles provided a second quantitati measure in relation to muscle
activation, allowingtion of whether injury influenced the time
taken for activation of all four muscles. The second temporal measure used,
therefore, was the time span (in seconds) for the sequence of activation of
the first ([Msub1) and fourth ([Msub4) muscles ([O, Msub1-Msub4]). The
incorporation of a time reference into the sampling procedure and the computer
acquisition of EMG and limb-position data allowed for a determination of these
temporal measures.
The EMG signals collected from the four monitored muscles during hip extension
were submitted to computer analysis to determine these measures for each of
the two limbs during the six trials for each subject. A special-purpose
computer program (language C) was written, in which the 2,500 samples of data
per second for each muscle for the 10-second recording period could be
analyzed. Data used for this program related to the raw EMG signals, the EMG
gain used to acquire data, the period for which the data were recorded, the
number of channels used, and the data rate. The number of data points was
calculated and then read in binary format. The data were stored after
multiplication by 100 to enable the program to use integer arithmetic where
possible in the analysis. The mean of the first 500 points was calculated and
subtracted from the raw data to enable the data to be centered on zero. The
data were then rectified about this mean value and smoothed (four passes,
100-point bandwidth) to remove the high-frequency components of the bursts yet
still leave the main burst shape. The filtering process was carried out by
using a filter subroutine that used a rectangular filter (the data were
linearly averaged over the bandwidth of the filter) and that allowed multiple
passes over the data.
The mean of the first 500 points was again calculated and subtracted from the
data to ensure that the mean value of the initial region was zero. The
location of the peak data point was identified, and from this data point, the
times at which the signal reached specified percentages of maximum could be
determined. For the purposes of this analysis, 5% of die maximum (peak value)
EMG signal was regarded as the onset of muscle activity. A second computer
program was used to rank the order in which each of the four muscles was
activated in each case. From this, the O, [Msub1]-[Msub4] calculation was
made. It also provided the incidence of each muscle occurring in each ranked
position.
As a preliminary investigation of onset times, prior to adopting the use of
the computer analysis, an independent "blind" visual observation of the EMG
signals on an IBM-compatible personal computer screen for a random selection
of subjects, trials, and muscles was performed to compare the accuracy of the
computer analysis with human inspection. For the gluteus maximus and hamstring
muscles, the computer analysis was found to give comparable results to those
obtained through manual inspection of the computer-displayed signal, suitably
magnified. Onset data for the lumbar erector spinae muscles were scrutinized
visually to determine those trials in which the proximity of the heart beat
signal to the signal of muscle activity made computer discrimination of the
onset of muscle activity impossible. In such cases, the onset data were
removed from the data set. Of the 372 possible values for muscle onset in the
entire sample, 24 values were rejected for this reason, as reflected in the n
values presented in Tables 3 and 4.
To determine the repeatability of the time of onset relative to hip motion, a
study was carried out using the analysis of six movement repetitions for each
subject. An analysis of variance was applied to determine the mean confidence
interval and its standard deviation and the "within-
subject-between-replication" variability for each of the four muscles. Results
demonstrated an acceptable level of repeatability of the measurement (Tab. 3).
[TABULAR DATA OMITTED]
Data Analysis
Data acquired for muscle activation during hip extension and for vibration
perception for both limbs were analyzed to investigate any differences between
the injured and control groups in muscle or sensory function in each limb. The
general linear model (GLM) of analysis of variance for unequal numbers was
selected as the most appropriate form of analysis for these data. This model
is used to reveal the influence of any independent variable on the dependent
variable and demonstrates whether there is any significant difference between
two groups of unequal numbers. The statistical package used was the SAS for
Personal Computers.(#)
Initially, to determine any group differences in vibration perception,
comparisonn strength required for subject perception at each
frequency were made between the injured and control groups by consolidating
the data for the two limbs in each case. Accordingly, "group" was included as
an independent variable in the GLM analysis. Similar comparisons were made
between groups for each of the two EMG measures. These analyses of the data do
not reveal whether differences exist in one side or the other, or in both, but
only that overall some alterations in vibration perception or in muscle
activation may be associated with injury.
Secondly, to determine whether vibration perception or muscle activation in
the injured or uninjured limb was significantly different from that on either
side of the control group subjects, further analyses were undertaken comparing
the side-to-side differences between groups.
Results
Vibration Perception
Analysis of data for vibration perception at each frequency demonstrated a
significant difference between the injured and control groups (P<.001). As
Figure 2 demonstrates, vibration strength needed to be greater for the injured
group than for the control group in order for the subjects to perceive the
stimulus.
A comparison of side-to-side differences between groups (uninjured versus
injured) showed that whereas there were significant differences between left
and right sides at only one of the four frequencies (200 Hz) for the control
group, there were significant differences between injured and uninjured sides
at three of the frequencies (150, 200, and 250 Hz) for the injured group (Tab.
4).
[TABULAR DATA OMITTED]
Comparison of the mean values for each side of the injured group subjects with
those of each side of the control group subjects showed that a greater
strength of vibration was necessary to reach threshold perception on both the
injured and uninjured sides of the injured group subjects than on either the
left or right side of the control group subjects. To determine whether the
threshold perception values for the uninjured side of the injured group
subjects contributed to these group differences, Student's t tests were
applied to the uninjured side of the injured group subjects versus each side
of the control group subjects. Significant differences were found to exist at
all frequencies (P<.05) (Tab. 5).
[TABULAR DATA OMITTED]
Electromyographic Analysis
Separate statistical analyses were performed on data for each temporal
variable (ie, O-H; O, [Msub1]-[Msub4]). To determine whether there were
significant differences between the injured and control groups, a GLM4
analysis was performed.
O-H. Reflecting the preparatory activation of the muscles prior to the limb
motion in hip extension, the onset times for each of the four muscles in
almost all instances preceded the time of commencement of the reference
activity (ie, hip motion), giving a negative value for O-H. The greater the
negative time span, the earlier the onset of activity of that muscle prior to
hip extension motion, whereas the smaller the negative time span, the later
the onset. The results of analyses of this variable need to be interpreted
with this in mind. Figure 3 represents typical EMG recordings of a control
group subject and an injured group subject.
With the data for the two sides consolidated, the GLM analysis showed that for
the gluteus maximus muscle, highly significant differences existed between the
injured group (mean = - 0.092) and the control group (mean=-0.349) (P<.001),
the time of onset of gluteus maximus muscle activity being significantly later
for the injured group than for the control group. That is, for the injured
group subjects, an overall delay in activation of the gluteus maximus muscle
was evident. For the hamstring and the left and right lumbar erector spinae
muscles, results of the GLM analysis showed that the group differences were
not significant.
The analysis of side-to-side differences for the gluteus maximus and hamstring
muscles revealed that for the control group, the time span (O-H) was
significantly greater on the left (stance) side than on the right (preferred
or skill) side (P<.05), indicating an earlier onset of gluteus maximus and
hamstring muscle activity on the left side for uninjured subjects (Tab. 6).
The side-to-side differences (injured versus uninjured sides) in the injured
group did not reach significance for either of these muscle groups. The
significantly later time of onset of gluteus maximus muscle activity for the
injured group compared with that of the control group (ie, with data for two
sides consolidated), however, suggested a delay in gluteus maximus muscle
activation on both sides of the injured group subjects. Examination of the
data in Tabl that this was so. A Student's t tes
the gluteus maximus muscle activity onset data for the uninjured side of the
injured group versus each side of the control group highlighted the
significant difference that existed (P<.0005). No significant side-to-side
differences were found to exist for either the left or right lumbar erector
spinae muscles.
[TABULAR DATA OMITTED]
O, [Msub1]-[Msub4]. Analyses of the consolidated data relating to the time
span between the onset of activity of the first and fourth muscles ([O,
Msub1-Msub4]) to be recruited revealed highly significant difference (P<.001)
between the injured and control groups. As Table 7 demonstrates, although the
mean time span for the control group was 0.036 second, it was 0.527 second for
the injured group, or 72% longer than for the control group.
The GLM analysis showed that there was no significant difference between sides
in the O, [Msub1-Msub4] time span for either group. Examination of the ranking
incidence indicated that the gluteus maximus muscle was almost always the
fourth muscle to be activated. This delayed activation was therefore
responsible for the greater O, [Msub1-Msub4] time span found in the injured
group.
The delayed activation in the gluteus maximus muscle was used as the variable
for a correlation analysis of muscle and sensory function. A Pearson
Product-Moment Correlation Coefficient analysis was applied to data for both
groups relating to vibration strength at threshold perception level and the
timing of onset of gluteus maximus muscle activity relative to hip extension
(O-H). Results demonstrated that a positive correlation existed for the
injured group between threshold vibration perception and gluteus maximus
muscle activation for the 250-Hz frequency (P<.05). That is, the less
sensitive the subjects were to vibration at 250 Hz, the longer the delay in
recruitment of the gluteus maximus muscle for hip extension. !!!BEGIN TABLE
Table 7. Comparison of Mean Time Span Between Onset of Activity of First and
Fourth Muscles.
Group N X (S)
Control (n= 11) 120 .306(a)
Injured (n=20) 229 .527(a)
[t.sub.df.sup.a]of error in ANOVA=6.73, P<.001. !!!END TABLE
Discussion
Significant differences in the sensory and muscle function of subjects with
severe ankle sprain were shown to exist when compared with that of uninjured
subjects. The decreased ability to perceive vibration appears to confirm the
views of Freeman[1] and Wyke[9] that a ligamentous/capsular injury influences
the integrity of local sensory receptors on the side of injury, presumably
through direct damage.
The significant delay in activation of the gluteus maximus muscle in the
injured group subjects and the positive correlation between a poorer
perception of vibration at 250 Hz and gluteal muscle delay suggests that joint
injury involving sensory receptors could influence the function of muscles
proximal to and removed from the injury side. Even though this study could not
determine cause and effect, this association provides support for the idea of
a reflex chain of events that occurs following injury, as proposed by Lewit[7]
and Janda.[8]
The normal activation behavior of the hamstring and lumbar erector spinae
muscles in the injured group can be viewed together with the delay in
activation of gluteus maximus muscle. A change in activation of all muscles
could have led to the assertion that all subjects in the injured group had a
motor regulation problem, as has been intimated by previous studies.[11,12]
The finding of significant activation changes in the gluteus maximus muscle,
however, only points to the possibility that such a change is associated with
the ankle injury. Because cause and effect were not the focus of this study,
further research is warranted to help clarify these interrelationships.
Differences in vibration perception and activation of the gluteus maximus
muscle on the uninjured side as well as the injured side of the injured group
subjects when compared with the control group subjects support the concept of
central adjustment of motor control following injury. This finding suggests
that a reflex chain of events is not limited to the side of injury, but that
there could also be implications for influences on the uninjured side.
These results suggest that as a result of injury to the ankle joint, the
activity of the hip extensors on both sides of the body is diminished. Whereas
Stokes and Young[3] and Iles et al[5] have demonstrated decreased extensor
activity at the site of injury, the results of this study suggest that there
could be a direct relationship of decreased activity of the extensors of thving
muscles not only remote from the site of injury but also
on the opposite side of the body. It is also possible that even after pain
following the ankle injury had ceased, the function of the gluteus maximus
muscle in extending the hip was compromised due, perhaps, to an alteration in
gait pattern established during the period of injury. Such possibilities are
the subject of further research.
The question could be asked whether subjects in the injured group had a basic
neurological deficit that led to their initial ankle sprain. Every attempt was
made to ensure that injured subjects included in this study had no history of
incoordination. As has been shown by this study, the injured group subjects
did, however, have a sensory deficit compared with the control group subjects.
Although it has been assumed that any differences from normal in the injured
group occurred as a result of injury, in a retrospective study the origin of
the differences cannot be determined. From the point of view of the management
of patients following ankle sprain, however, the origin of the deficit does
not affect the need for the physical therapist to pay due attention to the
need to improve sensory and motor function.[20]
This study has a number of implications for the physical therapist. In view of
the likelihood that a deficit in sensory function is associated with decreased
muscle activity around other joints, a rehabilitation program should include a
focus on improving sensory function. Because muscles respond in different ways
to peripheral injury, the results of this study suggest that the effects need
to be sought in areas remote from the site of injury. This study has examined
only some of the muscles around the hip. Further investigations could reveal
whether muscle function changes also occur in other joints following ankle
injury (eg, in the knee or vertebral joints), or indeed, whether they might
occur as a result of the effects of gluteal muscle delay.
The differences in sensory function and in the function of some muscles on the
uninjured side are also important in treatment. Whether such differences are
due to dysregulation at the cortical level or at a spinal level has still to
be determined. Nevertheless, the existence of differences highlights the need
to examine both sides of the body in assessment. These results emphasize the
importance of the physical therapist paying attention to motor control and to
the function of muscles around joints separated from the site of injury.
Conclusion
The results of this study have shown that both local sensory and proximal
muscle function changes are associated with unilateral severe ankle sprain and
that when some aspects of sensory and motor function deficits are considered,
there is a positive correlation between the two. If comprehensive and
effective management of injury is to be ensured, a holistic approach to
assessment is essential.
(*)Derriton (VP2) Mechanical Oscillator, Derriton Electronics Ltd, Sedlescombe
Rd, St Leonardson-Sea, Sussex, United Kingdom.
(dagger)Goodman's Power Oscillator (D5), Goodman Industries Ltd, Vibration
Division, Axion Works, Wembley, Middlesex, United Kingdom.
(double dagger)Medelec Ltd, Old Working Rd, Surrey, United Kingdom.
(section)Simens AG Minograph Chart Recorder, ZW22, Postgach 101212, D-8000,
Muchen 1, Federal Republic of Germany.
(parallel)Schaevitz (A411-0001) Accelerometer, Applied Measurement, Baltec
Systems, 26 Mayneview St, Milton, 4064, Brisbane, Queensland, Australia.
(#)SAS Institute Inc, PO Box 8000, Cary, NC 27511.
References
[1] Freeman MA. Instability of the foot after ankle injuries to the lateral
ligament of the ankle. J Bone Joint Surg [Br]. 1965;47:669-677.
[2] Ekholm J, Eklund G, Sk[phi]glund S. On the reflex effect from the kne(@
joint of the cat. Acta Physiol Scand. 1960;50:167-174.
[3] Stokes M, Young A. The contribution of reflex inhibition to arthrogenous
muscle weakness. Clin Sci. 1984;67:7-14.
[4] De Andrade JR, Grant C, Dixon A. Joint distension and reflex inhibition in
the knee. J Bone Joint Surg [Am]. 1965;47:313-322.
[5] Iles JF, Stokes M, Young A. Reflex actions of knee joint afferents during
contractions of the human quadriceps. Clin Physiol. 1990;10:489-500.
[6] Freeman MAR, Wyke B. Articular contributions to limb muscle reflexes. Br J
Surg. 1966; 53:61-68.
[7] Lewit K. Manipulative Therapy in Rehabilitation of the Motor System.
London, England: Butterworth & Co (Publishers) Ltd; 1985.
[8] Janda V. Muscles, motor regulation and back problems. In: Korr IM, ed. The
Neurologic Mechanism in Manipulative Therapy. New York, NY: Plenum Publishing
Corp; 1978:27-41.
[9] Wyke B. The neurology of jointnn R Coll Surg Engl. 1967;41:25-50.
[10] Chusive Neuroanatomy and Functional Neurologv. 16th ed.
Los Altos, Calif: Lange Medical Publications; 1976.
[11] Tropp H, Odenrick P, Gillquist J. Stabilometry recordings in functional
and mechanical instability of the ankle joint. Int J Sports Med.
1985;6:180-182.
[12] Gauffin H, Pettersson Y, Tegner Y, Tropp H. Function testing in patients
with old rupture of the anterior cruciate ligament. Int J Sports Med
1990;11:73-77.
[13] Freeman MA, Dean MR, Hanham WF. The aetiology and prevention of
functional instability of the foot. J Bone Joint Surg [Br]. 1965;46: 678-685.
[14] Gross MT. Effects of recurrent lateral ankle sprains on active and
passive judgments of joint position. Phys Ther. 1987;67:1505-1509.
[15] Barrack RL, Skinner HB, Buckley SL. Proprioception in the anterior
cruciate deficient knee. Am J Sports Med. 1989; 17:1-6.
[16] Schmitz TJ. Sensory assessment. In: O'Sullivan SB, Schmitz TJ. Physical
Rehabilitation: Assessment and Treatment 2nd ed. Philadelphia, Pa: FA Davis
Co; 1988: chap 6.
[17] Janda V. Muscle Function Testing. Boston, Mass: Butterworth; 1983.
[18] Roy S, Irvin R. Sports Medicine: Prevention, Evaluation, Management, and
Treatment, New York, NY: Prentice-Hall Press; 1983.
[19] Dyck PJ, Karnes J, O'Brien PC, Zimmerman IR. Detection Thresbolds of
Cutaneous Sensation in Humans. 2nd ed. In: Dyck PJ, Thomas PK, Lambert EH,
eds. Sydney, Australia: WB Saunders Co; 1984:1103-1138.
[20] Bullock-Saxton JE, Janda V, Bullock M. Reflex activation of gluteal
muscles in walking with balance shoes: an approach to restoration of muscle
function for chronic low back pain patients. Spine, 1993;18:704-708.
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Press for more (? for help) ! scroll
Citation: Patient Care, Feb 29, 1992 v26 n4 p6(15)
------------------------------------------------------------------------------
Title: Ankle: don't dismiss a sprain. (includes related article on
exercises that help an injured ankle) (Joint Trauma)
Authors: Birrer, Richard B.; Bordelon, R. Luke; Sammarco, G. James
------------------------------------------------------------------------------
Subjects: Ankle_Wounds and injuries
Sprains_Care and treatment
Wounds and injuries_Care and treatment
Reference #: A12045365
==============================================================================
Abstract: Ankles suffer many minor injuries that can become more serious if
treated improperly. A comprehensive diagnosis and treatment guide
provides information to prevent further injury.
==============================================================================
Press for more (? for help) ! scroll
Citation: Postgraduate Medicine, Jan 1991 v89 n1 p251(5)
------------------------------------------------------------------------------
Title: Ankle sprains are always more than 'just a sprain.' (includes
articles on ankle anatomy and rehabilitation of the sprained
ankle)
Authors: Stanley, Keith L.
------------------------------------------------------------------------------
Subjects: Ankle_Wounds and injuries
Sprains_Care and treatment
Reference #: A11898381
==============================================================================
Full Text COPYRIGHT McGraw-Hill Inc. 1991
When your patient sprains an ankle, you know what to do. The diagnosis is not
difficult, treatment is minimal, and the prognosis is excellent--right? Not
always. Reading Dr Stanley's article will help you diagnose, treat, and
rehabilitate with confidence.
Ankle sprains can occur under many circumstances, but they are most likely to
happen during participation in sports. Not surprisingly, ankle sprains are the
most frequent sports-related injury, accounting for an estimated 30% of all
such injuries (in basketball, an estimated 45% among men and 38% among
women).[1,2] Most ankle sprains are treated by primary care physicians.
Types of ankle injury
Lateral injuries to the ankle constitute about 90% of ankle sprains. These
usually occur when the ankle inverts and the foot supinates. External rotation
of the tibia may also occur. The most commonly involved structures include the
anterolateral capsule and the anterior talofibular, anterior tibiofibular, and
calcaneofibular ligaments (see Anatomy of the ankle).
Most injuries to the medial (deltoid) ligament involve pronation and eversion
of the ankle. There may also be a concomitant internal rotation of the tibia.
Most authorities agree that this type of injury constitutes less than 10% of
ankle sprains.[1]
In injuries that occur during high-energy stress to the ankle, the examiner
must always consider the possibility of related injury, such as injury to the
syndesmosis (rarely an isolated injury) as well as fracture. Fractures to look
for during examination of an ankle injury include avulsion fractures of the
malleoli or tarsal bones, epiphyseal fractures in young patients, and
fractures of the anterior process of the calcaneus or base of the fifth
metatarsal. The patient should also be evaluated for injury to the bifurcate
ligament.
Clinical evaluation
The mechanism of injury should be established during history taking. This
knowledge may aid in identifying injured structures and in determining the
force of the injury. The ambulatory status of the patient after the injury
should be ascertained.
Putting the patient in a comfortable position aids in examination of the
injured ankle. The active and passive range of motion of the injured ankle
should be observed. The uninvolved limb should always be evaluated to
determine the normal range of motion, muscle strength, and ligament laxity for
that patient. The location of any edema and ecchymosis should be noted, and
the vascular and neurologic status of the involved ankle should be assessed.
Palpation should begin away from the area of suspected injury. Palpation of
the forefoot, midfoot, and hindfoot structures is recommended before going on
to the ankle ligament structures. The base of the fifth metatarsal (the
insertion site of the peroneus brevis) should always be palpated, because it
is a common fracture site for inversion injuries of the ankle. The entire
course of the fibula as well as the syndesmosis should be palpated. This is
especially important with medial ligament injuries, since they are rarely
isolated and there is usually concomitant injury to the syndesmosis structures
or fibula (eg, Dupuytren's or Maisonneuve fractures).
The ligament structures, both medial and lateral, should be palpated next and
may be stressed to determine instability. Demonstration of a positive anterior
drawer sign (ability to sublux the talus anteriorly out of the ankle mortise)
is probably the most common clinical indicator of instability. The test should
be done with the foot in neutral and plantarflexed positions. The test for the
anterior drawer sign is done by stabilizing the tibia with one hand and
attempting to translate the talus anteriorly by force applied to the calcaneus
with the other hand.
Radiographic evaluation
Radiographic evaluation is a vital part of the examination of patients with a
sprained ankle, including those with only temporary ankle dysfunction. I
believe that all ankle sprains in skeletally immature patients should be
evaluated radiographically. X-ray films should be scrutinized to determine if
the ankle morten maintained. The types of fractures me
previously should be ruled out, as well as medial, lateral, or posterior
malleolar fractures.
The usefulness of adjunctive studies, such as stress roentgenography and
arthrography, is controversial[1,3-6] and should be left to specialists. These
studies as well as computed tomography (CT), magnetic resonance imaging, and
CT arthrography are beyond the scope of this article.
Grading ankle injury
Most physicians use a grading system of 1 through 3 to classify the severity
of ankle sprains. However, much debate about this system continues, especially
regarding differentiation between a severe grade 2 and a grade 3
injury.[1,4,6,7]
GRADE 1--Patients with this level of injury usually exhibit localized
tenderness (but no instability), normal range of motion, and little or no
functional disability.
GRADE 2--This level of injury has a wide range of symptoms. Moderate to severe
pain, edema and ecchymosis, and abnormal range of motion are common. Range of
motion may sometimes be severely impeded. There may or may not be instability
or pain during anterior drawer testing. Grade 2 injuries are characterized by
incomplete tearing of ligament fibers.
GRADE 3--This level of sprain is much more disabling than grade 2. There is a
marked deficit in range of motion, and ambulation is usually impossible.
Marked pain, edema, and hemorrhage are present. Complete disruption of the
ligament is usual.
Treatment
Treatment depends on the severity of injury. While controversy exists about
proper treatment of severe grade 2 and grade 3 injuries, most investigators
agree that nonsurgical treatment is appropriate in most cases.[1,2,4-8] There
is also debate on early mobilization versus immobilization. The literature
seems to indicate that, compared with immobilization, an early return to
athletics or work activity combined with early mobilization does not increase
the incidence of treatment failure.[9]
GENERAL MEASURES--Early treatment of ankle sprains includes protection, rest,
the application of ice and compression, and elevation. Ice may be applied by
ice pack, by placing the foot in a slush bucket or iced whirlpool, or by
cryotemp (Jobst Cryo Temp System) combined with compression provided by an
elastic support garment. Ice should be applied for 15 to 20 minutes during
every 1 to 2 waking hours, and this therapy should be continued for at least
72 hours. Contrast baths may then be initiated. Caution should be exercised to
avoid frostbite or nerve injuries during prolonged cryotherapy. Compression
may be accomplished through use of a felt or foam horseshoe pad applied with
an elastic wrap, splinting, air or gel stirrup braces, support garments, or
taping.
The typical emergency department treatment of applying an elastic bandage and
sending the patient home on crutches has little or no place in the care of
ankle sprains. The foot should not be held in an equinous position. If the
diagnosis is uncertain, a posterior splint or posterior sugar-tong splint may
be used to protect the ankle. These splints provide compression and protection
and still allow cryotherapy.
GRADE 1 SPRAINS--These injuries should be treated with ice and compression.
Motion should be restricted to prevent inversion or eversion. Nonsteroidal
anti-inflammatory drugs may be used, but their efficacy is not well
established except to speed improvement in functional capacity.[10]
Rehabilitation should begin on the first day after injury (see Rehabilitation
of the sprained ankle).
GRADE 2 SPRAINS--These injuries require an individualized treatment plan that
depends on the severity of injury and level of functional disability. Ice,
compression, and elevation are again appropriate.
How to protect the ankle and whether to use early mobilization or
immobilization must be decided for each patient. The literature supports early
mobilization.[1,2,7-9] If cast immobilization is used, it should be for a
short term (10 to 14 days) and followed by use of an ankle brace and
rehabilitation. A better alternative may be the use of a commercially
available cast-brace (tibial walker), which immobilizes the ankle for weight
bearing but allows removal of the device for physical therapy and
rehabilitative exercises.
GRADE 3 SPRAINS--Accurate diagnosis is of utmost importance in treatment of
grade 3 injuries. The controversy over surgical versus medical treatment is
still debated in the literature. Surgical treatment is outside the scope of
this article, but a published study by Brand and colleagues[3] is available
for review. Surgical intervention may be indicated if a diastasis of the
syndesmosis cannot be reduced or if the integrity of the ankle mortise cannot
be maintained with cast immobilization.
Some phns opt for 3 to 6 weeks of immobilization for patients with grade
3 ankle sprains. Another alternative would be 10 to 14 days of cast
immobilization, followed by application of a cast-brace and rehabilitation.
Cast-bracing may also be used initially to allow earlier physical therapy and
mobilization.
Physicians should realize that ankle sprains are significant injuries. They
can have serious sequelae or even cause disability if inadequately or
inappropriately treated. One cliche that should be deleted from physicians'
vocabularies is "it's just a sprain." Not all ankle sprains are identical.
Diagnosis, treatment, rehabilitation, and prognosis should be individualized
for each patient.
Anatomy of the ankle
The osseous structures usually involved in ankle sprains include the talus,
calcaneus, tibia, and fibula. The talus sits on the anterior two thirds of the
calcaneus in a mortise formed by the tibia and its medial malleolus and the
fibula and its lateral malleolus. Because the talus is wider anteriorly, the
ankle has greater osseous stability when in a neutral position (90%) or in
dorsiflexion.
The ligamentous anatomy may be divided into medial and lateral structures. The
medial ligaments, although collectively called the deltoid ligament, are
actually several different structures arranged in two groups: deep (anterior
and posterior tibiotalar) and superficial (tibionavicular and tibiocalcaneal).
The lateral ligaments include the anterior and posterior talofibular and the
calcaneofibular. The anterior talofibular ligament is taut in equinus
(plantar) flexion and inversion. The calcaneofibular ligament is not stressed
during inversion if the anterior talofibular ligament is intact, but it can be
stressed during inversion in dorsiflexion.
The syndesmotic ligaments must also be mentioned. These are currently
recognized as vital to ankle stability and, when injured, possibly the
greatest contributors to chronic ankle instability.[1,2] The syndesmotic
ligaments are the anterior and posterior tibiofibular, the inferior
transverse, and the interosseous.
References
[1]Balduini FC, Vegso JJ, Torg SS, et al. Management and rehabilitation of
ligamentous injuries to the ankle. Sports Med 1987;4(5):364-80 [2]Chapman MW.
Sprains of the ankle. In: American Academy of Orthopaedic Surgeons
instructional course lectures. Vol 24. St Louis: CV Mosby, 1975:294-308
Rehabilitation of the sprained ankle
Rehabilitation is the key to recovery from ankle sprains and should begin on
the first day after injury in most situations. The program must be customized
on the basis of the severity of injury and the patient's normal level of
activity.
Patients with grade 1 ankle sprains can begin a comprehensive rehabilitation
program on the day of the injury, including range-of-motion exercises,
stretching of the Achilles tendon, and isometrics or manual resistance
exercises (figure 1). Resistance exercises with a sport cord or surgical
tubing can be initiated early (figure 2). Double- and single-leg toe raises on
a flat surface, progressing to a step or incline board, should be included.
Proprioceptive training may be accomplished with exercises on a balance board
or balance beam or simply with single-leg standing with eyes closed. As
symptoms allow, exercise such as swimming or stationary bicycling may be
added, gradually progressing to straight-ahead jogging with no turns to stress
the ankle.
Depending on the athletic ability and expectations of the patient, the next
step in the program would be more stressful patterns of running. These
exercises should be done with either an ankle brace or ankle taping in place.
The patient's return to full activity is dependent on successful progression
through each step of the rehabilitation.
Grade 2 and grade 3 injuries require customized programs. Usually,
range-of-motion exercises can be safely done only in plantar flexion and
dorsiflexion early in the course of treatment. Stretching the Achilles tendon
by using a towel to help dorsiflex the foot can also be started early.
Isometrics or manual resistance exercises may be begun in the initial phase of
treatment. As range of motion and stability improve and symptoms of pain and
edema subside, resistance exercises with tubing, proprioceptive training,
swimming, and bicycling may be added.
If the patient is not progressing as expected or is having problems with the
rehabilitation program, then medically supervised physical therapy may be
indicated.
References
[1]Balduini FC, Vegso JJ, Torg JS, et al. Management and rehabilitation of
ligamentous injuries to the ankle. Sports Med 1987;4(5):364-80
[2]Vegso JJ,Harmon LE 3d. tive management of athletic ankle injuriesn Sports
Med 1982;1(1):85-98
[3]Brand RL, Collins MD, Templeton T. Surgical repair of ruptured lateral
ankle ligaments. Am J Sports Med 1981;9(1):40-4
[4]Chapman MW. Sprains of the ankle. In: American Academy of Orthopaedic Surgeons
instructional course lectures. Vol 24. St Louis: CV Mosby, 1975;294-308
[5]Drez D Jr, Young JC, Waldman D, et al. Nonoperative treatment of double
lateral ligament tears of the ankle. Am J Sports Med 1982;10(4):197-200
[6]Kay DB. The sprained ankle: current therapy. Foot Ankle 1985;6(1):22-8
[7]Nemeth VA, Thrasher E. Ankle sprains in athletes. Clin Sports Med 1983;2(1):217-24
[8]Linde F, Hvass I, Jurgensen U, et al. Early mobilizing treatment of ankle
sprains. Scand J Sports Sci 1986;8(2):71-4
[9]Wilkerson GB. Treatment of ankle sprains with external compression and
early mobilization. Phys Sportsmed 1985;13(6):83-90
[10]Dupont M, Beliveau P, Theriault G. The efficacy of antiinflammatory medication
in the treatment of the acutely sprained ankle. Am J Sports Med 1987;15(1):41-5
Dr Keith L. Stanley, MD is a family physician trained in primary care sports
medicine, practicing in Tulsa, Oklahoma. He serves as team physician for the
University of Tulsa, Oral Roberts University, the Tulsa Drillers AA baseball
team, and Tulsa Union High School.
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