Ankle Sprains: Expedient Assessment and Management

Thomas H. Trojian, MD, MMB; Douglas B. McKeag, MD, MS

Emergencies Series Editor: Warren B. Howe, MD

THE PHYSICIAN AND SPORTSMEDICINE - VOL 26 - NO. 10 - OCTOBER 98

In Brief: Most ankle injuries occur from excessive inversion, but it is important to be able to differentiate a simple inversion sprain from a potentially disabling injury. Expedient diagnosis includes first screening for deformities and then performing specific tests like the anterior drawer and side-to-side test. To optimize assessment, the examiner needs to take advantage of the preswelling period on the sidelines. Physicians can treat most ankle injuries nonoperatively, taking steps to ensure a quick return to play. Fracture signs and treatment are covered in a comprehensive table.

Ankle sprains are the most common athletic injury (1). Most involve injury to the lateral supporting ligaments from an inversion incident (2). The risk of ankle injuries varies by sport; they make up 45% of all injuries in basketball, 31% in soccer, and 25% in volleyball (1). In professional, college, and high school football, ankle sprains account for 10% to 15% of all time lost to injury. Yet these injuries are often minimized.

In addition to common ankle sprains, primary care physicians will see uncommon ankle injuries that need urgent care. Appropriate treatment can help patients avoid chronic ankle pain, laxity, or arthritis (3). Keeping a high index of suspicion for subtle, unusual injuries around the ankle will increase patients' quality of care.

Detail of Two Joints

The ankle consists of two joints: the talar mortise and the subtalar joint (4,5). The mortise is shaped like an inverted "U" bounded by the distal fibula and tibia (figure 1) and allows plantar flexion and dorsiflexion. Inside the "U" is the trapezoid-shaped talar dome; its greater anterior width gives the ankle more stability in dorsiflexion. The subtalar joint allows for inversion, eversion, and internal and external rotation.

The ligamentous structures of the ankle can be divided into three groups: tibiofibular, medial, and lateral complexes. The tibiofibular ligament stabilizes the ankle mortise and allows little movement between tibia and fibula.

The medial complex (figure 2) consists of the strong, fan-shaped deltoid ligament, which limits eversion of the ankle and lateral displacement of the talus. The medial malleolus will often fracture before this ligament tears.

The lateral complex (figure 3) consists of three ligaments: anterior talofibular, calcaneofibular, and posterior talofibular, which resist internal rotation, anterior displacement, and inversion. The anterior talofibular ligament is the most frequently injured in the ankle.

Muscles and tendons act as secondary stabilizers and are often injured. The peroneus longus is the main everter of the ankle. The anterior tibialis acts in dorsiflexion. The posterior tibialis inverts and plantar flexes the foot, and the Achilles tendon also acts in plantar flexion.

Initial On-Field Management

All ankle injuries need immediate on-the-field assessment by the athletic trainer or team physician. The goal is to evaluate the athlete quickly and identify any serious injury. Mechanism and position of the ankle at the time of injury are important. If the injury is minor, a full evaluation can be completed on the sideline. The initial survey needs to screen for any deformities. The athlete with no deformity can try to bear weight, which will help in grading the injury. (Inability to bear weight tends to indicate instability and thus a more serious injury.)

The physician needs to be prepared to stabilize any fracture or dislocation and transport the patient. If an athlete has an ankle deformity, axial traction and relocation should be attempted only once. Neurovascular assessment and documentation and urgent transport are essential after relocation or if relocation is not possible. When an ambulance is not available, transport in a large vehicle such as a station wagon is needed so the patient can lie supine.

Sideline or Office Evaluation

When the athlete's ankle is not deformed, the best opportunity for accurate diagnosis often comes on the sideline. Initially, palpation for crepitus and ligament testing will be difficult with an anxious athlete and global pain.

After the athlete relaxes, however, the initial pain decreases and what we like to call the "golden period" begins. During this period, there is no swelling, the initial pain has subsided, and guarding is not yet present—all of which facilitate a fruitful physical exam. (If a physician is not on site, the athletic trainer can take advantage of this period.) One caveat regarding the "golden period" is that a stable fracture may produce crepitus over the fracture site without causing initial tenderness.

History. A well-thought-out history can lead to the proper diagnosis most of the time. Mechanism of injury is very helpful (3), but if the injury occurred rapidly, the athlete may not know the mechanism. Important questions to ask are:

• How did it happen (inversion, eversion, dorsiflexion, etc)?

• Where does it hurt (table 1)?

• Did the intensity of pain make you stop playing (ruptured ligament, fracture)?

• Were you able to bear any weight right away (fracture, severity of injury)?

• Have you injured this or the other ankle before (to identify recurrent sprain, fractures, normal contralateral ankle)?

Table 1. Useful Tests for Various Ankle Injuries
Injury Location	Specific Injury	Useful Test
Lateral	Inversion sprain Lateral malleolus fracture Osteochondritis dissecans Peroneal tendon subluxation Bifurcate ligament avulsion	Anterior drawer, talar tilt X-ray as per Ottawa ankle rules Mortise view ankle x-rays Resisted dorsiflexion and eversion X-rays
Medial	Medial ankle sprain Medial malleolus fracture Posterior tibialis tendon injury Flexor hallucis longus tendinitis	Eversion stress X-ray as per Ottawa ankle rules Single heel-rise test Resisted first-toe flexion
Posterior	Achilles tendon rupture Os trigonum fracture	Thompson's Weight-bearing lateral x-ray, tenderness on passive plantar flexion
Anterior	Syndesmosis sprain Dorsiflexion injuries Anterior tibialis tendon injury	"Squeeze," external rotation Side-to-side Resisted dorsiflexion
Other	Avulsion fracture, 5th metatarsal Maisonneuve fracture	Palpation tenderness, foot x-rays Palpation tenderness, fibula x-rays

Physical exam. Examining the athlete's uninjured ankle provides a useful reference point and helps reduce anxiety for examination of the injured ankle. Shoe and sock removal is important for performing a proper examination and evaluating neurovascular status.

Any swelling or ecchymosis should be noted (5). The athlete should move the joint through all directions, then the physician should move the ankle through the six ranges of motion: plantar flexion, dorsiflexion, and inversion and eversion in plantar flexion and dorsiflexion. Results are compared with the uninjured side. The examiner also palpates the ligaments, tendons, and bones, paying close attention to any feeling of crepitus, tenderness, or swelling.

Strength testing is the last piece in the general exam. The physician should test inversion and eversion in plantar flexion and dorsiflexion by resisting active range of motion and comparing with the other ankle. Special tests for joint stability are also important.

Specific tests. The anterior drawer test (figure 4) assesses the integrity of the anterior talofibular ligament (5). However, initially its reliability may be suspect: A positive anterior drawer test within 48 hours of injury suggests a tear of the anterior talofibular ligament, but the test has a large number of false-negatives. If the test is performed 4 to 5 days postinjury, however, it has a sensitivity of 86% and specificity of 74% (6).

Talar tilt can be used to assess the deltoid ligament and the calcaneofibular ligament by eversion and inversion stressing, respectively. However, this is an unreliable test for ligamentous rupture with poor interrater reliability (6).

The side-to-side test (7) (figure 5) assesses widening of the ankle mortise caused by instability of the tibiofibular ligament. It is important in dorsiflexion injuries.

Thompson's test (figure 6) evaluates Achilles tendon continuity. It has a sensitivity of 96% and specificity of 93%.

The squeeze test (figure 7) and external rotation stress test (figure 8) help diagnose syndesmosis injuries (8).

Radiographs. The Ottawa ankle rules help guide ordering of radiographs for acute ankle and midfoot injuries. The rules cannot be applied if the examiner cannot palpate the bone because of excessive swelling.

The rules state that an ankle x-ray series is necessary only if there is pain on or superficial to the malleoli and any of these findings: (1) the inability to bear weight either immediately or in the emergency department (patient cannot take four steps) or (2) bone tenderness from 0 to 6 cm up the posterior edge or on the tip of either malleolus (9,10). These rules, however, were derived from the emergency department experience—an athlete at the field may initially have no tenderness at the site of fracture, only crepitus.

A foot x-ray series is necessary only for midfoot pain and any of these findings: (1) an inability to bear weight, both immediately and in the emergency department or (2) bone tenderness at the navicular or the base of the fifth metatarsal. These rules, if properly applied, will have about 100% sensitivity.

Ankle Injury Differential

On-site primary care physicians must be knowledgeable about a variety of soft-tissue and bony ankle injuries.

Lateral inversion sprain. The lateral sprain—the most common ankle injury—accounts for 85% of all ankle sprains (2). After an inversion injury, the lateral ligaments are stretched or torn, usually from anterior to posterior. Grading the injury (table 2) (11) can help with prognosis.

Table 2. Grading of Lateral Ankle Sprains and Return to Play (11)
Grade	Anterior Drawer Test	Talar Tilt Test	Return to Play
1	Negative	Negative	1-10 dy
2	Increased laxity	Negative	2-4 wk
3	Positive	Positive	5-8 wk with optimal rehab

All lateral sprains can be treated conservatively with protection, rest, ice, compression, and elevation (PRICEMMM, table 3). Crutches may be beneficial until pain-free weight bearing is achieved. A felt horseshoe, taped with an open basket weave technique or secured with elastic bandage, around the ankle initially will decrease swelling and aid in recovery. Ankle taping or bracing and proprioception retraining are often needed.

Table 3. 'PRICEMMM' Mnemonic for Treating Ankle Sprains Protection with ankle bracing to prevent reinjury while ligament heals Rest for injured ankle until normal heel-toe gait is restored Ice on ankle to decrease swelling and relieve pain Compression as soon as possible to decrease swelling Elevation: the initial step for reducing swelling Medication: NSAIDs or acetominophen for pain relief Mobilization early on when pain free to expedite return to play Modalities: exercise and proprioception training to prevent reinjury

Medial eversion sprain. Medial sprains are commonly seen in wrestlers. The tibia and strong deltoid ligament make eversion sprains less likely than lateral sprains (10% versus 85%) (7). However, 75% of ankle fractures occur on the medial side. Tears of the deltoid ligament can be detected by laxity or tenderness on eversion stress testing. Deltoid ligament tears point to other injuries that may require surgery, like a Maisonneuve fracture (see below), syndesmosis injury, distal fibular fracture, or avulsion fracture of the medial malleolus. Medial sprains otherwise can be treated like inversion sprains.

Syndesmosis sprain. The syndesmosis is stabilized by the interosseous membrane and the anterior and posterior inferior tibiofibular, transverse tibiofibular, and interosseous ligaments. The mechanism of syndesmosis (high ankle) sprains is uncertain but is postulated to be external rotation and hyperdorsiflexion (8). Syndesmosis sprains range from 1% to 11% of all ankle sprains, with the higher rate of injury occurring in contact sports. This injury, unlike the lateral sprain, has little swelling and lacks recurrence. Patients typically have tenderness over the anterior inferior tibiofibular ligament and proximally along the interosseous membrane. The squeeze, external rotation stress, and side-to-side tests are important in the diagnosis.

If a serious ligament tear is suspected, external rotation stress radiographs should be obtained. More than 5 mm of widening of the tibiofibular clear space indicates a complete rupture.

Delayed healing of syndesmosis sprains is typical, with recovery time of 55 days as compared with 35 days for a grade 3 lateral sprain. Treatment should involve non-weight bearing with advancement to a walking boot.

Bifurcate ligament injury. Because the bifurcate ligament is taut with plantar flexion and inversion, injury to it usually occurs with violent dorsiflexion, forceful plantar flexion, or direct trauma. It is associated with up to 19% of ankle inversion sprains. This mechanism can avulse the anterior process of the calcaneus.

A bifurcate sprain or avulsion fracture is often mistaken for a lateral ankle sprain because pain and swelling are near the lateral malleolus. The point of maximal tenderness is found midway on a line connecting the tuberosity of the fifth metatarsal and the distal tip of the lateral malleolus. Treatment of an avulsion fracture of the calcaneus should include a non-weight-bearing cast for 4 weeks. These injuries can produce pain for many months.

Achilles tendon rupture. Rupture of the Achilles tendon is often seen in older, deconditioned athletes (7). It is also seen in the younger athlete who has had prolonged inactivity because of another injury. Mechanism of action is rapid plantar flexion as in turning to sprint up court in basketball. The site of rupture is in the area of poor circulation 2 to 6 cm above the os calcis. Patients will feel a sharp pain in the Achilles and often state that it sounded like someone shot them.

Treatment is controversial. Casting is a reasonable option, especially if the tear is more than 2 cm from the calcaneal attachment. Surgery should be considered for the elite athlete to minimize the chance of rerupture.

Peroneal tendon subluxation or dislocation. The peroneus longus and brevis tendons lie in the shallow groove posterior to the fibula. Subluxation or dislocation of these tendons is not common but can happen with an inversion sprain. Disruption of the retinaculum or a fracture of the posterior edge of the fibula can cause dislocation of the tendon (12). This can be detected by palpating over the tendon with active dorsiflexion and eversion of the foot and ankle. The examiner will feel the tendon sublux, or the maneuver will elicit pain. Patients typically report pain with walking and with walking on the balls of the feet.

Conservative treatment consists of a U-shaped felt pad with ankle taping for primary dislocation. Surgical referral is warranted for lateral pain and a lack of stability. Postsurgical recovery time is at least 8 weeks.

Flexor hallucis longus injury. The flexor hallucis longus passes through a fibro-osseous tunnel behind the medial malleolus (13). Injury to this ligament is seen in dancers or other athletes who stand on tiptoe or on the balls of their feet. It is not typically associated with other injuries and can be misdiagnosed as Achilles tendinitis or as posterior tibialis tendinitis (14). Palpation of the sheath with active and passive ranges of motion of the hallux will reproduce symptoms. Treatment is conservative with rest, ice, nonsteroidal anti-inflammatory drugs, and an inflexible shoe.

Lateral periostitis. Lateral periostitis, or jumper's ankle, can occur in high-jumpers prior to takeoff in the planted foot (5). The foot is dorsiflexed and everted suddenly, thereby causing trauma to the talus from the distal fibula. Diagnosis can be difficult. Symptoms are similar to those of a lateral sprain but without anterior talofibular ligament tenderness. Palpation of the lateral talus with the foot in plantar flexion and inversion elicits pain. Treatment is rest and a G-in. medial heel wedge to prevent trauma.

Os trigonum injury. In this injury, severe plantar flexion (15) causes lateral posterior triangle pain. Resisted eversion will be pain-free, but forceful passive plantar flexion should reproduce symptoms. A bone scan or MRI can aid diagnosis. Treatment involves a short leg cast in 15° plantar flexion for 1 to 3 weeks. Steroid injection into the posterior triangle can be helpful.

Anterior tibialis tendon injury. The anterior tibialis tendon accounts for 80% of the dorsiflexion power of the ankle. It is rarely injured acutely, most often in elderly people, and produces pain on the dorsum of the foot. It can rupture or avulse from its site of insertion. Foot drop is common, and resisted dorsiflexion will be weak or tender. Typical treatment is surgery.

Fractures. Fractures constitute about 15% of ankle injuries and can coexist with ligament injuries. A complete discussion is not possible here, but some of the fractures associated with ankle sprains are covered in table 4 (15-18).

Table 4. Diagnosing and Managing Ankle Fractures
Site or Type	Characteristics and Findings	Treatment	Comments
Malleolus	Injuries that extend across an imaginary line drawn through the top of talar dome on AP x-ray considered unstable	Referral for unstable fxs; closed reduction, postreduction x-rays, casting and non-weight bearing for stable fxs
Epiphysis of tibia
Type 1 (Salter-Harris)	Localized swelling or minimal widening on x-ray	Casting for 2-4 wk	Be wary of "ankle sprain" in prepubescent patients since ligaments are stronger than physis at this age. Good to excellent healing for types 1-3; poor prognosis for types 4 and five.
Type 2	Metaphyseal fx into physis on x-ray	Closed reduction, long leg cast
Type 3	Epiphyseal fx into physis on x-ray	Referral to surgeon
Type 4	Fx through both metaphysis and epiphysis on x-ray	Referral to surgeon
Type 5	Narrowing of physis on x-ray	Referral to surgeon
Osteochondral	Weak ankles, crepitus, locking, deep pain, recurrent swelling	Casting if fragment not avulsed from talar dome; otherwise, surgical intervention	Often missed initially; may follow compression injury of talar dome.
Posterior tubercle of talus and os trigonum	Mechanism is severe plantar flexion of foot; patient has lateral posterior triangle pain; resisted eversion pain free; passive plantar flexion mimics symptoms	Short leg cast in 15° of plantar flexion for 4 wk; surgical excision occasionally	Occur in dancers, runners, soccer players.
Avulsion of fifth metatarsal	Inversion injury can avulse plantar aponeurosis from proximal tuberosity; produces tenderness at base of 5th metatarsal	Symptomatic care in cast shoe or hard shoe
Jones fracture	Tenderness at base of 5th metatarsal	Surgical screw fixation followed by non-weight-bearing cast	Common in basketball players and ballroom dancers
Lateral process of talus	Inversion injury; seen on mortise view but difficult to see on lateral view; bone scan or CT scan may help identify	Nondisplaced fxs: short leg cast for 6 wk, 4 wk non-weight bearing; displaced fxs: surgical intervention	Often missed for months because of proximity to lateral ligaments. Common in snowboarders.
Maisonneuve fracture	Eversion injury often associated with deltoid ligament sprain; pain and x-ray findings on proximal third of fibula; involves interosseus membrane	Referral for internal fixation	Often misdiagnosed; important to palpate entire fibula with eversion injuries.
Calcaneus	Extra-articular fx often from twisting forces; intra-articular fx often from fall from height; both involve pain with walking or inability to bear weight; CT can delineate two types	Extra-articular: non-weight-bearing cast; intra-articular: surgical referral	Extra-articular fxs often heal well.
Cuboid
Subluxation	Occurs during pronation; pain over lateral side of foot, often along sinus tarsi; pain is elicited by pressing on plantar aspect of cuboid in dorsal direction; running, cutting, jumping markedly increase pain	Repositioning cuboid by holding the forefoot with thumbs over plantar surface of cuboid and 'whipping' the foot into plantar flexion while thumbs push cuboid dorsally	Mostly seen in classical ballet dancers and distance runners.
Fracture	Uncommon but can occur with inversion and plantar flexion; mimics severe sprain or fx of anterior process of calcaneus	Short leg cast for nondisplaced fx; displaced fx requires surgery
Subtalar dislocation	Violent plantar flexion and inversion of foot produce medial dislocation; dorsiflexion and eversion lead to lateral dislocation; foot is deformed in both types	Reduction under general anesthesia	85% are medial. Neurovascular assessment is critical.
AP = anteroposterior, fx = fracture

Safe Return to Play

Many ankle injuries will not prevent an immediate return to action, but return to play is a case-specific decision. A few guidelines will help with this complex decision:

• A patient who has a stable injury should not return to play if that injury may become unstable.

• Pain-free range of motion is important.

• The athlete needs to complete functional testing pain free. Example: walking, jogging (forward and backward), figure eights, zigzags, and one-foot hops.

Using these guidelines and knowing the differential diagnosis, the team physician will be able to return a player to competition safely.

Widespread Knowledge

Primary care physicians need to be familiar not only with acute assessment and management of ankle sprains, but also with the many other injuries in the differential diagnosis, for they will see most of them over time.

References

1. Garrick JG: The frequency of injury, mechanism of injury, and epidemiology of ankle sprains. Am J Sports Med 1977;5(6):241-242
2. Tropp H, Askling C, Gillquist J: Prevention of ankle sprains. Am J Sports Med 1985;13(4):259-262
3. Trevino SG, Davis P, Hecht PJ: Management of acute and chronic lateral ligament injuries of the ankle. Orthop Clin North Am 1994;25(1):1-16
4. Netter FH: The CIBA Collection of Medical Illustrations, vol 8: Musculoskeletal System, Part 1: Anatomy, Physiology, and Metabolic Disorders. West Caldwell, NJ, CIBA-GEIGY Corp, 1991, pp 106-110
5. Renström PA, Konradsen L: Ankle ligament injuries. Br J Sports Med 1997;31(1):11-20
6. van Dijk CN, Lim LS, Bossuyt PM, et al: Physical examination is sufficient for the diagnosis of sprained ankles. J Bone Joint Surg (Br) 1996;78(6):958-962
7. McKeag DB, Hough DO: Common sports-related injuries and illnesses: pelvis and lower extremity. Section E: ankle, in McKeag DB, Hough DO: Primary Care Sports Medicine. Dubuque, IA, 1993, Brown & Benchmark, pp 433-448
8. Boytim MJ, Fischer DA, Neumann L: Syndesmotic ankle sprains. Am J Sports Med 1991;19(3):294-298
9. Stiell IG, Greenberg GH, McKnight RD, et al: Decision rules for the use of radiography in acute ankle injuries: refinement and prospective validation. JAMA 1993;269(9):1127-1132
10. Chande VT: Decision rules for roentgenography of children with acute ankle injuries. Arch Pediatr Adolesc Med 1995;149(3):255-258
11. Chorley JN, Hergenroeder AC: Management of ankle sprains. Pediatr Ann 1997;26(1):56-64
12. Sammarco GJ: Peroneal tendon injuries. Orthop Clin North Am 1994;25(1):135-145
13. Frey CC, Shereff MJ: Tendon injuries about the ankle in athletes. Clin Sports Med 1988;7(1):103-118
14. Conti SF: Posterior tibial tendon problems in athletes. Orthop Clin North Am 1994;25(1):109-122
15. Thordarson DB: Detecting and treating common foot and ankle fractures. Part 1: the ankle and hindfoot. Phys Sportsmed 1996;24(9):29-38
16. Baumhauer JF, Alvarez RG: Controversies in treating talus fractures. Orthop Clin North Am 1995;26(2):335-351
17. Waler JF Jr, Maddalo AV: The foot and ankle linkage system, in Nicholas JA, Hershman EB (eds): The Lower Extremity and Spine in Sports Medicine, ed 2. St Louis, CV Mosby Co, 1995
18. Quill GE Jr: Fractures of the proximal fifth metatarsal. Orthop Clin North Am 1995;26(2):353-361

Dr Trojian is an assistant professor of family medicine at UConn Health System, St Francis Hospital and Medical Center, Department of Family Medicine in Hartford, Connecticut. He is also a team physician at the University of Connecticut in Hartford and a member of the American Medical Society for Sports Medicine (AMSSM). Dr McKeag is the Arthur J. Rooney chair of sports medicine, a professor of family medicine and orthopedics, and the director of primary care sports medicine at the University of Pittsburgh. He is past president of the AMSSM and an editorial board member of The Physician and Sportsmedicine. Dr Howe is the team physician at Western Washington University in Bellingham and an editorial board member of The Physician and Sportsmedicine. Address correspondence to Douglas B. McKeag, MD, MS, Primary Care Sports Medicine, Room 215 School of Nursing, UPMC-Shadyside, 5230 Centre Ave, Pittsburgh, PA 15262.

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