PEDIATRIC ANNALS • Vol. 43, No. 12, 2014 e291

Abstract

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Mark E. Halstead, MD, is an Associate Professor, Departments of Orthopedics and Pediatrics, Washington University School of Medicine (St. Louis, MO).

Address correspondence to Mark E. Halstead, MD, Washington University Or-thopedics, 14532 S. Outer Forty Drive, Chesterfield, MO 63017; email: halsteadm@wudosis.wustl.edu.

Disclosure: Mark E. Halstead has no rel-evant financial relationships to disclose.

doi: 10.3928/00904481-20141124-08

Ankle injuries are common in sports, and the ankle sprain is the most common of ankle

injuries, but there are many injuries that can mimic a sprain. In the skeletally immature ath-

lete, bone injuries, particularly those that affect the physis, are more likely to occur than a

ligamentous injury. Knowledge of relevant anatomy, physical exam, and appropriate im-

aging can assist the primary care provider in accurately diagnosing the majority of ankle

injuries in the young athlete. [Pediatr Ann. 2014;43(12):e291-e296.]

Pediatric Ankle Sprains and Their ImitatorsMark E. Halstead, MD

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Ankle injuries are common and are second in incidence only to hand and wrist injuries in the

young athlete. Ankle sprains comprise the majority of these injuries. In the skeletally immature athlete, however, in-juries that affect the physes occur more frequently than a sprain. Careful consid-eration of all diagnostic possibilities is important to determine the correct treat-ment plan.

EPIDEMIOLOGYAlmost 50% of all ankle sprains are

sports related, with the majority occur-ring in basketball (41%), football (9%), and soccer (8%). In youth soccer, foot and ankle issues account for 18% of all injuries.1 The peak age for all ankle sprains is between 15 and 19 years, with a rate of 7.2 sprains per 1,000 person-years.2 The mean peak ankle sprain in-cidence for males occurs between ages 15 and 19 years and for females occurs between ages 10 and 14 years.2

ANATOMYThe ankle is a hinge joint, with most

motion occurring primarily in the dor-siflexion and plantar flexion positions. Side-to-side movement is achieved through the subtalar joint. Three bones comprise the main ankle joint—the dis-tal tibia, distal fibula, and talus (Figure 1). Three ligaments provide stability to the lateral ankle—the anterior talofibu-lar ligament (ATFL), calcaneofibular ligament (CFL), and posterior talofibu-lar ligaments (PTFL). The deltoid liga-ment complex provides stability to the medial ankle. The distal tibiofibular liga-ments, along with the syndesmosis (the membrane that connects the tibia and fibia), provide additional stability, and when these are injured, the diagnosis is a “high” ankle sprain.

PHYSICAL EXAMINATIONThe same general physical examina-

tion principles that are applied to other

joints can also be applied to the ankle. First, one should inspect the ankle for swelling, bruising, deformities, and skin integrity, and then ask if the patient has been using any assistive devices such as a brace or crutches to ambulate. Second, range of motion should be evaluated both actively and passively. In an acute

injury, passive motion by the examiner may elicit significant pain and should not be forcefully conducted. Strength should be assessed with resisted dorsi-flexion, plantar flexion, inversion, and eversion. Strength may be diminished in an acute injury secondary to pain.

Palpation should be conducted over all bones, ligaments, and tendons around the ankle and midfoot in an acute ankle injury. Particular note should be made regarding tenderness over either the lat-eral or medial malleolus, base of the fifth metatarsal, and navicular bone because tenderness in these areas warrants fur-ther evaluation with X-rays.

Special tests for the ankle include the anterior drawer test, talar tilt test, exter-nal rotation stress test, and squeeze test. The anterior drawer test is to determine laxity of the ankle joint secondary to an ATFL rupture. The test is performed with the foot and ankle at a 90-degree angle or a “neutral” position. The examiner uses one hand cupped around the heel while the other hand stabilizes the tibia. The hand holding the heel is used to try to anteriorly translate the foot relative to the ankle. A test is considered positive when there is increased laxity and a vis-ible gap laterally while performing this test. Pain does not need to be provoked to consider this a positive test. The talar

tilt test is performed to assess for poten-tial rupture of the ATFL and CFL. While keeping the ankle in a position similar to the anterior drawer test, the examiner will invert the ankle. If both the ATFL and CFL have been injured, there will be an increased angle between the tibia and talar dome compared with the uninjured side. This test may be difficult to con-duct in the setting of an acute injury as this motion may be limited due to pain and patient guarding.

Two tests for syndesmotic injuries (ie, “high” ankle sprains) include the squeeze test and the external rotation stress test. The squeeze test is conducted with the patient sitting on an exam table with the leg hanging over the table with the knee at 90 degrees of flexion. The fibula and tibia are compressed near the mid-calf. A positive test produces pain at the syndesmosis. The external rota-tion stress test is also performed with a patient sitting with the leg hanging with the knee flexed to 90 degrees. Passive external rotation of the foot and ankle are performed while keeping the ankle in a neutral position at 90 degrees of flexion. A positive test is indicated by pain at the syndesmosis.

IMAGINGWhen ordering radiographs of the

ankle, the standard series includes an anterior-posterior (AP) view, lateral view, and mortise view (AP view with foot internally rotated about 20 de-grees). In some cases, further evaluation with a computed tomography (CT) scan may be warranted, particularly in cases in which fractures are noted to extend intra-articularly and further determina-tion of displacement may be needed for surgical planning. Magnetic resonance imaging (MRI) is typically not indicat-ed for most acute ankle injuries in the young athlete.3

Clinical decision rules have been de-vised (initially for adults and then vali-dated in children older than age 5 years)

Two tests for syndesmotic injuries include the squeeze

test and the external rotation stress test.

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and are named the Ottawa Ankle Rules (OAR) (Table 1).4 A meta-analysis evaluating the accuracy of the OAR in children revealed a pooled sensitivity of 98.5% and specificity of 7.9%-50%.5

The pooled negative likelihood ratio is 0.11, which would make use of the OAR acceptable for ruling out a fracture of the ankle.5 The estimated missed fracture rate was 1.22%.5 These studies also es-timated a reduction in ankle radiographs performed by 5.4%-43.8% if the OAR are applied.5 Other radiograph decision rules, including the Low-Risk Exam and Malleolar Zone Algorithm, were found to be inferior to OAR in a head-to-head comparison study.6

PHYSEAL FRACTURES Salter Harris Type I Fractures of Distal Fibula

One of the most common ankle inju-ries in the young athlete, which is often misdiagnosed as an ankle sprain, is a Salter Harris type I fracture of the dis-tal fibula. The mechanism is identical to that for an ankle sprain—inversion of the ankle. Given the relative weakness of the physis compared with the lateral ligaments, the physis is the structure that often fails first, resulting in this frac-ture. Careful examination for the area of maximal tenderness will help dis-tinguish between a ligament sprain and a physeal fracture. For a lateral ankle sprain, maximal tenderness will be over

the ligaments themselves, whereas the Salter Harris type I fracture will have maximal tenderness over the physis of the lateral malleolus. Often, soft tissue swelling is noticeably more pronounced directly over the lateral malleolus in the Salter Harris type I fracture rather than the anterior lateral ankle and the area around the ATFL, as in a lateral ankle sprain.

Radiographs are often normal, al-though some may demonstrate slight widening of the physis and/or soft tissue swelling adjacent to the physis. Treat-ment is often with a walking boot or short leg walking cast for 3-4 weeks fol-lowed by another 1 or 2 weeks to transi-tion back to normal sporting activities. Consideration should be made to follow up any physeal fractures for growth ar-rest up to 1 year following the injury.

Juvenille Tillaux FractureThe juvenile Tillaux fracture is a

fracture unique to the adolescent popu-lation that occurs as the adolescent is nearing skeletal maturity, often between the ages of 12 and 15 years. The injury is a Salter Harris type III fracture that extends from the anterior lateral distal tibial physis and exits intra-articularly through the epiphysis7 (Figure 2). The mechanism is typically through an ever-sion mechanism. Management is dic-tated by the amount of displacement. Traditionally, >2 mm of displacement is

thought to be the criteria for the need of open reduction and internal fixation of the fracture.7,8 A CT scan may be used to more accurately determine the degree of fracture displacement (Figure 3). Non-displaced fractures can be treated with a nonweight-bearing cast followed by a walking boot for a total of 6 to 8 weeks.7 With prolonged immobilization, there likely will be a need for physical ther-apy. Time to return to sports is variable but should be based on the athlete’s re-turn to normal range of motion, strength, and function.

Triplane FractureA triplane fracture is a Salter Harris

type IV fracture of the distal tibia. Simi-lar to the Tillaux fracture, these often occur as the athlete is nearing skeletal maturity, usually between the ages of 12 and 15 years. These typically occur from an external rotation force to the foot. Several variants of this fracture have been described. The fracture, when viewed from the AP radiograph, may appear similar to a juvenile Tillaux frac-ture. The lateral view will usually dem-onstrate a Salter Harris type IV fracture affecting primarily the posterior aspect of the tibia. A CT scan is often used to determine the significance of the frac-ture and displacement. Surgical reduc-

Figure 1. Ankle anatomy. Reprinted with permission from Blackburn et al.21

TABLE 1.

Ottawa Ankle RulesAn ankle radiograph is only required if

there is any pain in a malleolar zone (de-

fined as the area around the medial and

lateral malleolus) and any of the following :

1. Bone tenderness of the posterior edge

or tip of the lateral malleolus

OR

2. Bone tenderness of the posterior edge

or tip of the medial malleolus

OR

3. Inability to bear weight both immedi-

ately and in the emergency department

Data from Stiell et al.4

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tion may be necessary, and referral to an orthopedist is warranted if this fracture is identified.9

LIGAMENTOUS INJURIESInjuries to the ankle ligaments are

more likely to occur in the skeletally mature young athlete than in the skel-etally immature athlete. Once the physis has closed, the bone no longer acts as the “weak link,” allowing the ligaments to take more of the force. Injuries can oc-cur to any of the three lateral ankle liga-ments—the deltoid ligament complex, or the distal tibio-fibular ligaments and syndesmosis.

Lateral Ankle Sprain The lateral ankle sprain, which con-

stitutes the majority of all ligamentous injuries of the ankle, occurs through an inversion mechanism. A common cause is landing from a jump on an opponents’ foot and rolling off the foot. Pain and swelling is usually localized over the an-terior lateral ankle. The degree of swell-ing and bruising can vary dramatically. Tenderness is most commonly localized over the ATFL, but may be present in other areas depending on when the pa-

tient is evaluated. Immediately follow-ing the injury, stiffness and additional swelling may produce tenderness to pal-pation in other areas.

Initial treatment may consist of the use of crutches or a walking boot in cas-es where normal weight bearing is too painful. The RICE (rest, ice, compres-sion, and elevation) treatment method should be encouraged immediately after the injury. Early range of motion may help reduce swelling and hasten recov-ery. Weight bearing can be allowed, and should be encouraged as soon as the pa-tient has a normal heel-to-toe gait. Pain control may be achieved through use of acetaminophen or nonsteroidal anti-in-flammatory drugs. A randomized study comparing acetaminophen and naproxen showed they were equally effective in reducing pain and disability when taken regularly for 5 days following an acute ankle sprain.10 Physical therapy is rec-ommended to help restore normal func-tion and to reduce repeat injuries.

Ankle sprains may be graded based on the severity of the injury. In a grade I in-jury, the ligament has a mild stretch with no gross tearing. The anterior drawer test may be painful but does not demonstrate

any significant laxity. Grade II injuries involve partial tearing of the ligament. The anterior drawer test demonstrates moderate laxity but with a firm end point. In a grade III injury, the ligament is com-pletely torn. Anterior drawer test shows significant laxity and no firm end point. Return to play can be variable following an ankle sprain. Some athletes may have a mild enough injury to be able to return in a few days and others may take months to fully recover. Generally, the higher the grade of sprain, the longer the recovery. Typically, once an athlete can demon-strate a normal heel-to-toe gait without pain or a limp and can progress through functional testing relevant for the sport they are returning to, such as running, cutting side-to-side, or jumping without limitations, the athlete can be considered able to return to play. In a study of high school athletes, no difference was found in the time to return to play in a new ver-sus a recurrent ankle sprain.11

A variant of a sprain is the avulsion fracture of the lateral malleolus. An avulsion fracture may be a common finding on an ankle radiograph follow-ing an inversion injury. These injuries are often equivalent to a sprain, and in this author’s experience may be treated the same as a lateral ankle sprain rather than as a fracture.

Deltoid (Medial) SprainThe deltoid ligament complex is

comprised of multiple bands.12 This ligament typically is injured through an eversion mechanism. Because the ankle has limited eversion ability compared with inversion ability, the deltoid liga-ment is less commonly injured than the lateral ankle ligaments. Careful physi-cal examination of the entire ankle and lower leg should be conducted to evalu-ate for any lateral-sided pain or injury in association with the medial ankle in-jury. If both medial and lateral pain is present, one should suspect a more sig-nificant injury of the ankle, including an

Figure 3. Juvenile Tillaux fracture seen on com-puted tomography scan. Note that the medial tibial physis is fused.

Figure 2. Juvenile Tillaux fracture.

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injury to the syndesmosis, and ankle ra-diographs should be performed. These radiographs are used to determine if an unstable ankle exists from the injury. Evaluation for widening of the medial or tibiofibular clear space should be per-formed, and if widening is present a re-ferral should be made to an orthopedist. If no widening is present, conservative management can be utilized. This often consists of a period of immobilization in a weight-bearing short leg cast or walk-ing boot (usually for 3 weeks), coupled with physical therapy. Return to play often is prolonged following a deltoid sprain compared with a lateral sprain, and it often takes at least 4 weeks to re-turn to full participation.

High Ankle SprainA less common but more severe in-

jury to the ankle ligaments is what is often referred to as a high ankle sprain. This injury is caused by excessive ex-ternal rotation of the ankle in relation to the foot, usually when the ankle is in dorsiflexion. Ligaments that can be af-fected include the anterior and/or pos-terior inferior tibiofibular ligament, the interosseus ligament, and syndesmo-sis.13 Standard ankle radiographs should be performed to assess for widening of the tibiofibular or medial clear space, as this indicates an unstable ankle and may require surgical management. Physical exam should include evaluation with the external rotation stress test and squeeze test and careful palpation of the entire length of the fibula, as a proximal fibula fracture may occur in association with a syndesmotic injury (Maisonneuve frac-ture). Athletes should be counseled that return to play may take 6 weeks or lon-ger after a high ankle sprain. Immobili-zation and non-weight bearing early on may be necessary to help facilitate pain relief and healing. Consideration should be made for referral to an orthopedist or sports medicine specialist if there is sus-picion of a high ankle sprain.

OSTEOCHONDRAL DEFECTS OF THE TALUS

Osteochondral defects of the talus can occur in either the medial or lat-eral aspect of the talus. Although often a result of trauma, this lesion can also occur without a history of trauma.14 De-pending on the severity of the lesion, nonoperative or operative treatment may be appropriate. Cessation of activity and referral to an orthopedist or sports medi-cine specialist for further evaluation is warranted.

AVULSION FRACTURE OF BASE OF FIFTH METATARSAL

Avulsion fracture at the base of the fifth metatarsal is commonly seen with an inversion mechanism while the ankle is in plantar flexion (Figure 4). The forces of the peroneus brevis tendon and lateral band of the plantar fascia pulling at its attachment at the base of the fifth meta-tarsal have been implicated in producing this injury. A normal apophysis (a center of growth that a tendon attaches to but does not provide longitudinal growth)

can exist at the base of fifth metatarsal and often is mistaken for a fracture. This apophysis can become painful, and this condition is known as Iselin’s apophysi-tis. A rule of thumb in distinguishing the normal apophysis from a fracture is by the orientation of the lucency. The nor-mal apophysis runs parallel to the long axis of the bone, whereas a typical avul-sion fracture at the base of the fifth meta-tarsal has a lucency that is perpendicular to the long axis of the bone (Figure 5). Treatment of the fifth metatarsal avul-sion fracture often consists of the use of a walking boot or postoperative shoe for a period of 4-6 weeks.15 Return to sports typically occurs after the radiographs demonstrate evidence of healing, the bone is nontender, and the athlete has re-gained normal pain-free range of motion and function.

PREVENTIONComplete prevention of ankle inju-

ries in sports is likely not possible. Pro-prioceptive training programs have been found to be an effective means of reduc-

Figure 4. A typical fifth metatarsal avulsion frac-ture. The fracture line is perpendicular to the length of the bone.

Figure 5. A normal fifth metatarsal apophysis at the base. The fragment is parallel to the length of the bone.

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ing the likelihood of a repeat ankle sprain in the athletic population but have not been conclusively demonstrated to help with primary prevention of sprains.16 Ex-ternal bracing with a lace-up ankle brace has been demonstrated to be effective in reducing the likelihood of primary and recurrent sprains in high school basket-ball and football players.17,18 Bracing has also been found to be more cost effec-tive in prevention of secondary injury in comparison with both a neuromuscu-lar training program and a combination program of bracing and neuromuscular training.19 An unsupervised, home-based proprioceptive program has also been found to be effective in reducing recur-rent ankle sprains.20

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18. McGuine TA, Hetzel S, Wilson J, Brooks A. The effect of lace-up ankle braces on injury rates in high school football players. Am J Sports Med. 2012;40:49-57.

19. Janssen KW, Hendricks MR, van Mechelen W, Verhagen E. The cost-effectiveness of measures to prevent recurrent ankle sprains: results of a 3-arm randomized controlled trial. Am J Sports Med. 2014; 42(7):1534-1541.

20. Hupperets M, Verhagen E, van Mechelen W. Effect of unsupervised home based pro-prioceptive training on recurrences of ankle sprain: randomised contolled trial. BMJ. 2009;339:b2684.

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