More than 2 million people in the United States injure their ankle every year.1 In this country, the risk of a significant ankle injury is 1 in 10,000 person days,2 so that the average individual will experience approximately 2.7 ankle injuries during his or her lifetime.3 In the athletic population, ankle injuries are the most common injury, accounting for 10% to 30% of all musculoskeletal injuries.4 At an estimated $300 to $900 to diagnose and completely rehabilitate an ankle sprain, we spend approximately $2 billion a year, which is equal to the amount spent on coronary artery bypass surgery.5
Pediatrie residency training programs have not emphasized the diagnosis and management of common musculoskeletal injuries.6 Because pediatricians care for a young, healthy, and active population, it is important to fee! comfortable in the diagnosis, acute care, and the long-term rehabilitation of routine ankle sprains. Like any other disease process, knowledge of the disease (epidemiology, anatomy, mechanism of injury, and clinical manifestations), physical examination techniques, ancillary tests, and expected progression of recovery are essential for effective management.
Eighty-five percent of all ankle injuries are ankle sprains, and of those sprains, 85% are inversion injuries, 5% are eversión injuries, and 10% are combined injuries.7 Ankle sprains are responsible for approximately 15% of the participation time lost to injury* and on the average take 36 to 72 days to completely rehabilitate.5 Sports with the highest ankle sprain injury rates emphasize jumping, "cutting," or running on uneven ground. Basketball, both men's and women's, has the highest incidence of ankle sprains (38% to 45% of all their injuries), followed by football, Volleyball, soccer, and cross country running.4
The ankle is primarily a bony ligamentous complex. The ankle joint itself can be broken down into two parts that work in concert like a universal joint: the mortise and the subtalar joint. The ankle mortise consists of the distal tibia and fibula superiorly and the dome of the talus inferiorly. It is an inherently stable hinge joint and primarily allows for plantar/flexion (foot pointing downward) and dorsiflexion (foot pointing upward) of the foot. Regarding the stability of the talus in the mortise, the dome of the talus is wider anteriorly than it is posteriorly. Therefore, when the foot is in dorsiflexion, the wide portion of the talus fits snugly into the mortise and is more stable. When the thinner portion of the talus is engaged with the foot in plantarflexion, the ankle is less stable, as in the athlete who is landing on his or her toes while running or jumping. Inferior to the ankle mortise is the subtalar joint, which is made up of the talus superiorly and medially and the calcaneus inferiorly and slightly laterally. This joint is less stable than the mortise and allows for inversion, eversión, and internal and external rotation of the ankle.
Figure 1. Lateral ligament complex of the ankle. (Reprinted with permission from Hergenroeder AC. Diagnosis and treatment of ankle sprains: a review. Am J Dis Child. 1990;144:809-814. Copyright ©1990, American Medical Association.)
The ligamentous structures can be divided into three groups: the lateral, the medial, and the tibiofibular complexes. The lateral complex is the most often injured and is comprised of three ligaments: the anterior talofibular ligament, calcane' ofibular ligament, and the posterior talofibular ligament (Figure 1). The anterior talofibular ligament is a weak, short, thin ligament extending from the anterior edge of the distal fìbula to the neck of the talus. It is the primary restraint to inversion forces when the foot is in the plantarflexed position. The calcaneofibular ligament is a stronger cordlike ligament extending from the distal-most part of the fibula beneath the peroneal tendons onto the lateral aspect of the calcaneus. It is the primary restraint to inversion forces when the foot is in the dorsiflexed position. The posterior talofibular ligament is a short, trapezoidal-shaped ligament that extends from the posterior edge of the distal fibula to the posterior aspect of the talus. It is the last ligament to be torn when the ankle is completely dislocated during an inversion injury. On the medial ankle is the strong, flat, fan-shaped deltoid ligament that extends from the medial malleolus to the navicular, anterior and posterior talus, and medial calcaneus (Figure 2). It is an effective primary restraint to eversión forces. Finally, the tibiofibular complex is comprised of the anterior and posterior tibiofibular ligaments and the syndesmosis (Figure 3). The tibioftbular ligaments are short ligaments that connect the distal fibula and tibia, and are oriented parallel to the mortise joint, while the syndesmosis is a thin strong membrane situated between and extending almost the entire length of the tibia and fibula. This complex is responsible for maintaining the tibiofibular relationship and in doing so, maintains the integrity of the superior portion of the ankle mortise.
Figure 2. Medical view of the ankle. (Reprinted with permission from Hergenroeder AC. Diagnosis and treatment of ankle sprains: a review. Am J Dis Child. 1990:144:809-814. Copyright ©1 990, American Medical Association.)
Although primarily a bony ligamentous complex, there are a number of muscles and nerves that may be injured during an ankle sprain. Two of the peroneal muscles (brevis and longus) originate at the lateral aspect of the middle one third of the fibula and pass posterior to the lateral malleolus and insert at the base of the 5th metatarsal and the heads of the first two metatareals, respectively. These muscles are the primary ankle evertere, and during an inversion ankle sprain, will fire as hard as possible to bring the ankle back to its normal position. Therefore, the peroneals are often injured during inversion sprains, and if weak from previous unrehabilitated injury, will predispose to repeat injury. Damage to one of the major nerves (sural, tibial, or peroneal) usually requires a fracture/dislocation, but even with mild sprains, proprioceptive fibers may be stretched, necessitating proprioceptive retraining (ie, balance) as part of the rehabilitation process.
Functional Classification of Ankle Sprains
Figure 3. Eversión ankle injury. (Reprinted with permission from Hergenroeder AC. Diagnosis and treatment of ankle sprains: a review. Am J Dis Child. 1990:144:809-814. Copyright ©1990, American Medical Association.)
MECHANISM OF INJURY, CLINICAL MANIFESTATIONS, AND FUNCTIONAL GRADING CLASSIFICATION
The history of the mechanism of injury is helpful in thinking about what structures are likely to be injured. Unfortunately, the events of the injury often occur so fast that patients cannot always give an accurate history. Commonly, a lateral ankle sprain occurs with the foot in plantarflexion with an inversion force applied, such as when landing from a jump in basketball and the patient describes "rolling" his or her foot under. The deltoid sprain often occurs with the foot in the dorsiflexed, abducted position with an eversión force applied, such as when a wrestler tries to get a wider stance on the mat. Damage to the tibiofibular complex can occur when the foot is forcefully rotated, such as in football when a player falls on top of the ankle of another who is lying prone. Patients who report a pop or snap are likely to have torn a ligament and possibly fractured a bone.
Information about what happened immediately after the injury can be helpful in estimating the extent of the injury. Were they able to continue in the game? Were they able to walk off the field or were they carried? Athletes who are able to continue playing probably have a milder injury compared to those who could not bear weight. Did it swell? immediate swelling generally reflects the degree of pathology although marked swelling can follow a mild injury. Also, questions regarding postinjury management can be useful. Specifically, if they appropriately used ice after the injury, the swelling will be well controlled and may understate the degree of the injury, in contrast to using hot soaks or a heating pad, which will cause marked swelling in even a mild injury. A history of previous ankle injuries is important because full rehabilitation may not have occurred and chronic functional instability may have been present prior to this injury. Chronic functional instability can be manifest as pain, stiffness, weakness in the ankle, lack of trust in "cutting" off that ankle, and recurrent minor ankle injuries. Preexisting medical problems or systemic complaints should be assessed in consideration of other causes of ankle pain, such as rheuinatologic, oncologie, and infectious causes.
The most useful grading system is one that helps to predict the progression to return to iull activities. A functional classification scale that is based on the signs and symptoms and degree of disability is the most clinically applicable (Table).
The examination of an injured ankle is important in establishing a working diagnosis and choosing the initial treatment. Examining the uninjured ankle first will allow approximation of "normal baseline" (assuming the other ankle has not been injured previously) and to allow the patient to know what to expect when the injured side is examined. In obvious cases of fracture and dislocation, it is of primary importance to evaluate neurovascular status with as little movement as possible. If there is no obvious deformity, patients should remove shoes and socks from both feet and roll up their pants legs so that both lower legs can be inspected for bony deformity, edema, ecchymosis, and anatomic variants.
Range of motion initially should be tested actively (what the patient can do on his or her own) against resistance provided by the examiner, and passively (what the examiner can do). The six cardinal movements need to be assessed: dorsiflexion, dorsiflexion with inversion and eversión, plantarflexion, and plantarflexion with inversion and eversión. If there is loss of dorsiflexion, the ankle will have less bony stability, as discussed earlier. Functionally, dorsiflexion can be assessed by having patients attempt a full squat with their heel on the floor, looking specifically at how far the lower leg can bend forward while keeping their heel on the ground.
Resisted range of motion will evaluate the integrity of the muscle-tendon unit. The examiner will have to distinguish weakness due to direct muscle tendon disruption versus pain associated with the contraction of the muscle as it moves the injured structures. The peroneal muscles are the most often injured and the most often unrehabilitated muscle group in the ankle. Peroneus brevis is best assessed in the plantarflexed foot with resisted eversión.
The final step is palpation of the seven areas that are most injured during ankle trauma: the entire length of the fibula, the medial malleolus, the base of the fifth metatarsal, the anterior, medial, and lateral joint lines, and the Achilles tendon complex. Point tenderness or crepitation is indicative of a fracture. If there is no evidence of fracture, passive and active range of motion should be compared looking for deficits that can be rehabilitated. The presence of a subluxating peroneal tendon may be reproduced with resisted eversión in the dorsiflexed position both nonweightbearing and weightbearing. The examiner may feel the tendon move and the patient will feel something pop or snap over the lateral malleolus.
Provocative testing of the ankle attempts to evaluate the integrity of the ligaments. They ate dependent on the experience of the examiner and the ability of the patient to relax. In a patient with a markedly swollen, painful ankle, provocative testing is useless because of voluntary and involuntary guarding secondary to muscle spasm.
The anterior drawer test (Figure 4) is performed with the patient's ankle in neutral (90° of dorsiflexion) and the knee flexed at 90° with one hand placed 2 to 3 inches above the joint line to stabilize the tibiafibuía and the other hand gripping the heel and applying an anterior force. If there is greater than a 5 mm difference from the uninjured side or a definite clunk at the endpoint, it is indicative of anterior instability with an incompetent anterior talofibular ligament. '
Figure 4. Anterior drawer test for anide instability. (Reprinted with permission from Hergenroeder AC. Diagnosis and treatment of ankle sprains: a review. Am J Dis Child. 1990;1 44:809-81 4. Copyright ©1990, American Medical Association.)
The inversion stress test is performed with the patient and examiner in the same position as the anterior drawer test but the hand that cups the heel will apply an inversion force in both neutral and planter flexion.The patient should not be taken past the point of pain. If there is more than 25° inversion on the injured compared with the uninjured side or a definite clunk at the endpoint suggesting subluxation, then calcaneofibular ligament incompetence may be present (Figure 5).
Although these techniques are less useful than the patient's functional history, in a patient with laxity on examination and who has been unable to progress in rehabilitation, surgical reconstruction may be indicated. The tibiofibular syndesmosis is tested by the examiner interlacing his or her fingers together behind the distal third of the tibia and fibula and using the heels of the hands to squeeze the tibia and fibula together. If there is a tear in the syndesmosis, the patient will experience pain with squeezing or even more so on release of the squeeze because with release, the "squeezed" bones pull apart and reproduce the tearing of the syndesmosis.
Finally, testing for peroneal subluxation is performed with the ankle positioned in dorsiflexion and everted against resistance. The patient will experience pain over the posterior aspect of the lateral malleolus, and the examiner may confirm the diagnosis by feeling the tendon subluxate anteriorly.
Figure 5. Inversion stress tilt test for ankle instability. (Reprinted with permission from Hergenroeder AC. Diagnosis and treatment of ankle sprains: a review. Am J Dis Child. 1990; 144:809-81 4. Copyright ©1990, American Medical Association.)
Functional testing along with the history of functional activities is important in the evaluation of the injury. Initial assessments include the ability to bear weight and walk on a flat surface. If the patient is able, have the patient perform 10 toe raises with 2 feet and then repeat on the injured foot/ankle. This will test both strength and endurance and can be used as criteria to return to a walk-jog program. A symmetric, pain-free five hop test, in which the patient hops as high as possible five times on each ankles, indicates strength, endurance, relative stability, and some balance parameters. If the patient can do this on the injured ankle as well as the uninjured, he or she can return to competition, but it does not signal the end of rehabilitation. The final test is the modified Romberg, which tests the patient's balance and proprioception. The patient balances on the injured leg alone, with eyes closed and arms outstretched, while the examiner is looking for how much unsteadiness occurs in the injured side compared with the uninjured side.
Every patient who twists his or her ankle does not need a radiograph. The Ottawa Rules are guidelines for the necessity of radiographs in the acute setting.10 These guidelines were developed in adults and have been validated in a small pediatrie population.11 Ankle radiographs, including an anteroposterior, lateral, and mortise views, are only necessary if there is pain in the area of the malleoli AND one of the following:
* inability to bear weight both immediately and in the emergency department (four steps) or
* bone tenderness at the posterior edge of the distal tibia or fibula.
A foot radiograph is only necessary if there is pain in the area of the midfoot AND one of the following:
* inability to bear weight both immediately and in the emergency department (four steps) or
* bone tenderness at the navicular or the base of the 5th metatarsal.
The usefulness of stress radiographs in the evaluation of ankle sprains has been seriously questioned. In the nonacute setting, radiographs should be considered in patients who have persistent symptoms or failure to progress despite adequate treatment and adherence to rehabilitation.
The most important entities to rule out in the differential diagnosis are fractures. About 15% of all ankle injuries have an associated fracture, usually in the tibia or fibula. There is a higher incidence of fracture in eversión injuries because a greater force is necessary to injure this strong stable complex. Prepubescent children are at risk of physeal injury because the ligaments are stronger than the physis at this age. Be very suspicious of prepubescent "ankle sprains."
Special attention to some fractures is necessary. Avulsion fractures of the base of the 5th metatarsal can occur during an inversion injury as the peroneal muscles attempt to prevent inversion. This must be differentiated from the Jones' fracture of the metaphysis of the base of the 5th metatarsal. This latter fracture occurs in an area of decreased vascularity resulting in a greater risk of nonunion. Fracture of the dome of the talus can be missed on initial presentation because it is difficult to palpate, plain films may be normal, and it is often painless.1
Peroneal neuropathies have been associated with fracture or severe inversion injuries. They will have delayed onset of pain from hours to days after the injury and progressive worsening of pain. They may have paresis, paresthesias, and nocturnal cramping. Other diagnoses to consider include fracture of the anterior process of the calcaneus, peroneal tendon strains, bone or cartilage loose bodies, and reflex sympathetic dystrophy.
WHEN TO REFER
Most ankle sprains can be managed without referral to a sports medicine specialist. All uncomplicated ankle sprains should have an attempt at full rehabilitation before considering surgery. There are few complications with functional rehabilitation, and there is no detriment to long-term outcome if surgery is delayed while rehabilitation is attempted.12 Those injuries that need to be referred include Jones's fracture, peroneal subluxation, or any unstable fracture. Unstable fractures include the following:
* any fragment that is displaced > 1 mm or widening of the ankle mortise > 1 mm.
* lateral malleolus fracture with lateral displacement of the talus,
* bimalleolar fracture,
* fracture of the fibular shaft with evidence of medial injury, and
* marginal fracture of the tibia involving more than 25% of the articular surface.
The pathophysiology of healing necessitates dividing treatment into two phases: 1) acute and 2) early mobilization with progressive, active rehabilitation. The goals of acute treatment of ankle sprains are to:
* minimize the swelling in and around the joint space,
* control pain,
* protect against further injury,
* promote healing, and
* start rehabilitation to minimize strength, flexibility, and endurance losses.
Early mobilization with a progressive rehabilitation program is necessary to obtain the following goals:
* restore range of motion, especially dorsiflexion,
* restore strength, especially the peroneal muscles,
* restore proprioception,
* maintain fitness level by cross training, and
* return to activity safely.
The acute management ideally begins the moment an injury occurs and continues until all swelling has resolved. The mneumonic to remember the essential elements of this management is PRICEMMMS, an extension of "RICEM" described elsewhere in this issue, applied to ankle injuries.
P=Protection from further injury by limiting the patient's exposure to inversión/eversión stress. Using an air stirrup will allow the patient to have dorsi- and plantarflexion while it limits inversion and eversión. It should be used continuously in the initial phases of healing. Once swelling and deficits in strength and flexibility are resolved, its use can be limited to exercise only. Casting had been used routinely in the past but has fallen out of favor secondary to the consequences of stasis and organization of edema, marked muscular atrophy, decreased bone density, and weakening of the bony ligamentous attachment. It may be an option in noncompliant patients.
R=Relative rest or not doing anything that hurts, including the use of crutches if the patient is limping.
I=Ice can be effective as long as there is swelling.14 The use of a bag of crushed ice directly on the skin for 20 minutes on the hour is safe and effective if there are no contraindications to the use of ice (ie, Raynaud's, peripheral vascular disease, impaired sensation, or cold hypersensitivity). Instructing patients that there will be a burning sensation that occurs 3 to 5 minutes from the start of icing may help them keep the ice on and get to the point of anesthesia. Heat has no role in the treatment of the acutely injured ankle.15
C=Compression (directed compression) is accomplished by using a horseshoe-shaped 1A inch felt pad or gauze on both the medial and lateral side in conjunction with compression hose or wrap. This directed compression helps promote résorption of edema out of the joint space where it will interfere with normal function.16
E=Elevation, optimally above the level of the heart but practically any elevation will improve venous return and decrease swelling.17
M=Medications (analgesics and antiinflammatories) do not improve the long-term outcomes of ankle sprains, but they have an important role in the control of pain and possibly inflammation after acute injury.
M=Modalities such as electrical muscle stimulation may assist with analgesia and in maintaining muscle strength and range of motion in the injured ankle.18
M=Mobilization (improving range of motion) should start on the day of injury with active plantarflexion and dorsiflexion ("ankle pumps") in a pain-free arc of motion in an attempt to maintain plantarflexion and dorsiflexion and augment edema mobilization. Writing the alphabet in the air with the big toe ("alphabets") as often during the day as possible will improve range of motion. Care to avoid inversion in range of motion and strengthening exercises will assist in preventing disruption of the healing tissues.
S=Strength training of the peroneal and gastrocnemius muscles should be started as soon as possible to minimize deconditioning. Rehabilitation should include high repetitions (sets of 10 to 20) of low resistance exercises in a painless arc of motion, which may necessitate isometric exercises (contraction against a stationary object so that the muscle contracts without moving the joint through any arc of motion).
EARLY MOBILIZATION AND PROGRESSIVE, ACTIVE REHABILITATION
Following the acute phase of treatment, the patient must be transitioned to a progressive, active rehabilitation program. This portion of the treatment entails providing a functional stepwise progression that introduces a higher level of stress to the ankle at each step. At this point in the treatment program, the patient may feel relieved that it is "just an ankle sprain" and after the pain and swelling have resolved, their rehabilitation is complete. Actually, the work has just begun as a premature return to competition will put them at risk for a more severe ankle injury. When the plan for rehabilitation is outlined, it will give the patient task-oriented goals as opposed to arbitrary time goals that can be frustrating if progress is not "on schedule" (Figure 6). The goal of long-term rehabilitation of ankle sprains is to minimize the incidence of symptoms of chronic functional instability. The strategy is to regain full strength, range of motion, and proprioception, while minimizing loss of cardiovascular fitness and time to return to work and sports. Patients must be involved in cross training to maintain their strength and endurance so that when their ankle is ready to return to practice, the rest of their body is also. Activities such as strength training, water jogging, swimming, and cycling can achieve these goals without putting the ankle at risk for reinjury. Familiarity with the patient's athletic interests is important because functional requirements vary between sports. For example, after a similar ankle sprain, a football lineman may be able to return to play sooner than a guard in basketball.
Range of motion is progressed from "ankle pumps" and "alphabets" to towel pulls and gastrocnemius/soleus Stretchs (Figure 7). The importance of recovery of dorsiflexion cannot be overstated. Exercises of the ankle with increasing elastic band resistance should begin as soon as the patient is able to perform them pain-free (Figure 7) and should be continued until the completion of all rehabilitation.Strengthening exercises should progress from isometrics to 3 sets of 10 toe raises with two feet then the injured foot/ankle alone. Once the patient can perform 10 single leg toe raises, he or she is ready to begin a progressive walk-jog program, in which the patient will start by walking on a circular track for 20 minutes per session. The next step, assuming the patient has no pain or swelling, is to progress to walking the curved portion and jogging the straight portion of the track, to be followed by jogging the entire track.
Figure 7. Flexible band exercises for resisted inversion (A), eversión (B), plantar flexion (C), and dorsiflexion (D). (Reprinted with permission from Adolescent Health Update. Copyright, American Academy of Pediatrics.)
Since the peroneal muscles are the primary evertors and as such the principle defense against inversion injuries, special attention is necessary for full rehabilitation of these muscles. Once the patient is showing progress in muscular strength and endurance in both the gastrosoleus and peroneal muscles, manifested as pain-free, stable repetitions of 10 single toe raises, the patient should begin proprioceptive retraining. Proprioception is assessed in a stepwise fashion starting with the ability to stand on one foot with and then without support. The next step is balancing with eyes closed with and without support. When the patient can maintain balance for 2 to 3 minutes as well on the injured side as the uninjured side, proprioception is essentially recovered.
Once the athlete is ready to return to practice as determined by the five-hop test, he or she should start with simple drills and progress to no restrictions. All exercises should be performed with the protective brace until the athlete has been released to play without restrictions. Use of a brace improves proprioceptive feedback19·20 and has a benefit over taping in that it can be readjusted during exercise.21
This article reviewed the basics of ankle diagnosis and rehabilitation. It is hoped that after reading this, pediatricians will have more confidence in caring for these injuries.
1. Peariman M, Leviellle D, DeleonibusJ, et al. Inversion lateral ankle trauma: differential diagnosis, review of the literature, and prospective study. J Foot Surg. 1987;26:95-135.
2. Baumhauet JF, Alosa DM, Renstrom PA, et al. A prospective study of ankle injury risk factors. Am } Spora MeA 1995;23: 564-5 70.
3. US Dept of Health and Human Services. HeMt United States 1984- Hyatttville, Md: National Centro for Health Statistics; 1984. DHHS publication (PHS) 851232.
4. Carnet JG. The frequency of injury, mechanism of injury, and epidemiology, of ankle sprains. AmJ Spora MoL 1 97 7:5:241-242.
5. Soboroff SH, Pappius EM, Komaroff AL. Benefit, risk, and cost of alternative approach to the evaluation and treatment of severe ankle sprain. CIm Orthop. 1984:183:160-168.
6. SlerlingJM, Landry GL. Sports medicine training during pediatrie residency. Arch Pe&erAdofeicMfti 1996;150t21l-215.
7. Bfoetrom L. Sprained ankles. III: clinical observations in recent ligament ruptures. Acca Cfer Stand. 1965 iI 30:560-569.
8. Bronrom L. Sprained anido, I: anatomic lesions in recent sprains. Acca CWr Scarni. 1964:128:483-495.
9. Landeros O, Frost HM, Higgíns CC. Posttraumatìc anterior ankle instability. Clin Ormop. 1968-,56: 169-1 78.
10. Sciell IG, Greenberg GH, McKnight D, et al. Decision rules for the use of radiography in acute ankle injuries: refinement and prospective validation. JAMA. 1993;269:1127-1132.
11. Chande VT. Decision rules for roentgenography of children with acute ankle injuries. Areft Pedwtr Adolesc MaL 1995; 149:255-258.
12. KannusP. Treatment for acute tears of the lateral ligaments of the ankle./ Bone Joint Sorg Am. 1991:73:305-312.
13. Yablon IG. Which ankle fractures can be managed conservatively? J MuicuJosltc! Mti 1984;Z5:19-26.
14. Basur RL, Shephard E, Mouias GL. ? cooling method in the treatment of ankle sprains. Practitioner. 1976:708-711.
15. Hocutt JE, J affé R, Rylander CR, et al. Cryotherapy in ankle sprains. AmJ Sports Mot 1982:10:316-319.
16. Wilkerson GB1 Horn-Kingery HM. Treatment of the inversion ankle sprain: comparison of different modes of compression and cryotherapy. J Orthop Sports Phji TVr. 1993:17:240-246.
17. Sims D. Effects of positioning on ankle edema. J Othop Sporti Pkys Tfvr. 1986;8:3034.
18. Reid DC. Sports injury Assessment and Rehabilitation. New York. NY: Churchill Livingstone; 1992.
19. Cartoli MJ, Rijke AM, Perrin DH. Effect of the Swede-O Ankle Brace on talar tilt in subjects with unstable ankles. J Spore Rehab. 1993:2:261-267.
20. Feuerbach JW, Gratiner MD. Effect of the Aircast on unilateral postural control: amplitude and frequency variables. J Ortfiop Sports Phys Ther. 1993:17:149-154.
21. ShapiroMS, KaboJM, Mitchell PW, et al. Ankle sprain prophylaxis: an analysis of the stabilizing effects of braces and tape. AmJ Sports Med. 1994;22: 78-82.
Functional Classification of Ankle Sprains