Ankle pain in the active child or skeletally immature adolescent: Overview of causes

INTRODUCTION — This topic will discuss causes of ankle pain in the active child or skeletally immature adolescent.

The evaluation of ankle pain, ankle sprains, and ankle fractures in children and young adolescents are discussed separately:

●(See "Foot and ankle pain in the active child or skeletally immature adolescent: Evaluation".)

●(See "Ankle sprain in adults: Evaluation and diagnosis".)

●(See "Syndesmotic ankle injury (high ankle sprain)".)

●(See "Ankle fractures in children".)

ANATOMY — The ankle consists of three interrelated joints: the tibiofibular, talocrural, and subtalar joints. The tibiofibular joint is made up of the syndesmosis and anterior/posterior tibiofibular ligaments and provides stability for the distal tibia and fibula. This stable unit is the superior portion of the talocrural joint where the dome of the talus fits snugly inferiorly (figure 1). The talocrural joint is stabilized by ligamentous structures medially (deltoid ligament (figure 2)) and laterally (anterior talofibular, calcaneofibular, and posterior talofibular ligaments (figure 3)) and primarily moves in the sagittal plane (dorsiflexion, plantar flexion (figure 4)). The talus articulates with the superior aspect of the calcaneus at the anterior and posterior articulations of the subtalar joint. The interosseous ligament and the bone anatomy make this a relatively stable joint that moves in the combined motions of pronation and supination.

EVALUATION — Ankle pain in the young athlete can originate in the bones (fractures) (figure 1 and figure 5), ligaments (sprains) (figure 3 and figure 2), nerves (figure 6), or muscles (strains) and tendons (tendinitis) (picture 1 and picture 2). History, physical examination, and, when indicated, plain radiographs are often sufficient to make the correct diagnosis. (See "Foot and ankle pain in the active child or skeletally immature adolescent: Evaluation".)

Plain radiographs of the ankle (anteroposterior, lateral, and mortise views) are indicated in all patients who cannot bear weight or ambulate four steps after an acute injury, who have bony tenderness or deformity on examination, or who demonstrate findings of osteochondritis dissecans (OCD; eg, talar tenderness or joint effusion), stress fractures, sinus tarsi syndrome (STS), and accessory ossicles.

The Low Risk Ankle Rule (figure 7) and the Ottawa Ankle Rules (figure 8) have been used in the pediatric population to identify patients who warrant imaging with some evidence that they help to reduce the need for imaging. (See "Ankle fractures in children", section on 'Imaging'.)

Localization of tenderness — The acuity of the condition and careful localization of tenderness on examination can help to narrow the differential diagnosis of ankle pain:

●Lateral ankle tenderness – Conditions associated with lateral ankle tenderness include:

•Acute pain (see 'Lateral' below)

-Fibular fracture (lateral malleolus)

-Anterior process fracture of calcaneus

-Ankle sprain (anterior to lateral malleolus) (figure 3)

•Chronic pain (see 'Lateral' below)

-OCD (anterior lateral talus)

-STS

-Peroneal injuries (picture 3 and picture 4 and picture 1)

-Os peroneum (picture 5)

-Exertional compartment syndrome (lateral)

-Lateral impingement related to symptomatic pes planus

-Tarsal coalition (see "Forefoot and midfoot pain in the active child or skeletally immature adolescent: Overview of causes", section on 'Tarsal coalition')

●Medial ankle tenderness – Causes of medial tenderness include:

•Acute pain (see 'Medial' below)

-Distal tibial fracture (medial malleolus)

-Medial ankle sprain (deltoid ligament) (figure 2)

•Chronic pain (see 'Medial' below)

-Flexor hallucis longus injuries (picture 6)

-Os tibiale externum (accessory navicular bone) (see "Forefoot and midfoot pain in the active child or skeletally immature adolescent: Overview of causes", section on 'Flexible pes planus (flat feet)')

-Posterior tibialis tendinitis (picture 7) (see "Heel pain in the active child or skeletally immature adolescent: Overview of causes")

-Tarsal tunnel syndrome (figure 6)

-OCD (posterior medial talus (image 1))

-Navicular stress fracture (see "Evaluation, diagnosis, and select management of common causes of midfoot pain in adults", section on 'Medial arch (navicular) injury')

●Anterior ankle tenderness – Conditions associated with anterior ankle tenderness include:

•Acute pain (see 'Anterior' below)

-Talus fractures (rare in children)

-Syndesmotic ankle injury (high ankle sprain)

•Chronic pain (see 'Anterior' below)

-Tibialis anterior tendinitis (picture 8)

-OCD (anterior medial talus (image 1))

-Exertional compartment syndrome

-Anterior impingement

●Posterior ankle tenderness – Conditions associated with posterior ankle tenderness include:

•Acute pain (see 'Posterior' below)

-Achilles tendon rupture (figure 9)

-Posterior process of the talus fracture (see "Talus fractures")

•Chronic pain (see 'Posterior' below)

-Achilles tendinitis/enthesitis (figure 9)

-Os trigonum syndrome (posterior impingement syndrome) (image 2)

-Talar stress fracture

-OCD (posterior medial talus)

-Achilles tendon enthesitis from reactive or juvenile idiopathic arthritis (at Achilles tendon insertion)

-Retrocalcaneal bursitis (see "Heel pain in the active child or skeletally immature adolescent: Overview of causes", section on 'Retrocalcaneal bursitis')

-Exertional compartment syndrome (deep posterior)

●Diffuse tenderness or nonspecific location – The following conditions are associated with diffuse or nonspecific localization of tenderness (see 'Diffuse or nonspecific location' below):

•Osteomyelitis of the tibia

•Infectious arthritis (eg, bacterial or Lyme arthritis)

•Bone tumor

ACUTE INJURIES

Lateral

Fibular fractures — Distal fibular fractures are the most common ankle fracture in children and adolescents. A child with a distal fibula fracture typically has a history of inversion of the ankle with swelling and pain localized over the lateral physis (lateral malleolus) (figure 4). Most patients are unable to walk or have significant limitation of ambulation. Physical examination demonstrates bony tenderness at the site of the fracture (fibular physis in the case of Salter-Harris I). Initial radiographs may not show a bony abnormality in patients with a Salter-Harris I fracture (figure 10). (See "Ankle fractures in children", section on 'Evaluation'.)

The diagnosis of ankle fractures is made based upon physical examination and imaging with plain radiographs. Imaging should be obtained in any patient with deformity and when physical examination suggests a fracture. The Low Risk Ankle Rule (figure 7) and the Ottawa Ankle Rules (figure 8) have been used in the pediatric population to identify patients who warrant imaging with some evidence that they help to reduce the need for imaging. (See "Ankle fractures in children", section on 'Imaging'.)

Anterior process fractures of the calcaneus — These fractures are commonly misdiagnosed as lateral ankle sprains based upon the location of pain and mechanism of injury. Anterior process fractures can occur as either an avulsion fracture at the insertion of the Y-shaped bifurcate ligament (that connects the anterior process to the cuboid and navicular bones) when the foot is forcefully adducted and plantar-flexed or a compression fracture secondary to forceful abduction of the forefoot. (See "Ankle fractures in children", section on 'Fracture classification'.)

Presentations of anterior process fractures of the calcaneus may be subtle, with the only findings being moderate pain and tenderness just distal to the insertion of the anterior talofibular ligament (ATFL). Plain radiographs are diagnostic. Magnetic resonance imaging (MRI) is indicated if plain radiographs are negative, but there is clinical suspicion or atypical ankle sprain progression. (See "Calcaneus fractures", section on 'Anterior process fracture' and "Calcaneus fractures", section on 'Avulsion of extensor digitorum brevis origin'.)

The management of ankle fractures is discussed separately. (See "Ankle fractures in children", section on 'Initial management'.)

Lateral ankle sprains — Ankle sprains most commonly occur after ankle inversion (figure 4). The ATFL (figure 3) is the first or only ligament to be injured in the majority of children and young adolescents. More severe injuries may involve the calcaneofibular ligament, and the most severe sprains will involve all three lateral ligaments. On physical examination, the patient typically has tenderness and swelling over the involved ligaments and, for mild and moderate sprains, can ambulate. The diagnosis of an ankle sprain is made clinically. Patients with atypical findings (eg, inability to ambulate, bony tenderness over the lateral or medial malleolus, base of the fifth metatarsal, or navicular bone) warrant plain radiographs to exclude a fracture.

Special examination maneuvers, grading, and management of ankle sprains are discussed separately as follows:

●(See "Ankle sprain in adults: Evaluation and diagnosis", section on 'Special tests'.)

●(See "Ankle sprain in adults: Evaluation and diagnosis", section on 'Grading'.)

●(See "Ankle sprain in adults: Management", section on 'Treatment'.)

Medial

Tibial fracture — Distal tibial physeal fractures are associated with eversion injuries and have a higher risk of long-term complications. Patients present with pain and swelling localized over the medial physis. Severe eversion injuries may also cause distal tibia and fibula fractures, creating instability of the ankle joint. Patients with obvious deformity or bony tenderness at more than one location (eg, lateral and medial malleolus) should not ambulate during evaluation due to this joint instability.

More severe inversion injuries in young adolescents with partially fused physes (near skeletal maturity) may cause juvenile Tillaux (image 3) or triplane (image 4) fractures that have a significant risk of growth arrest. (See "Ankle fractures in children", section on 'Fracture classification'.)

Medial ankle sprain — Medial ankle sprains occur after eversion injuries. They involve the deltoid ligament complex and are less common than lateral ankle sprains because the deltoid is the strongest of all the ankle ligaments. On physical evaluation, the patient will have swelling and tenderness to palpation over the deltoid ligament. Due to the strength of the ligament, a medial malleolus avulsion fracture is an important consideration in the skeletally immature patient. Thus, plain radiographs are typically warranted.

Special examination maneuvers, grading, and management of ankle sprains are discussed separately as follows:

●(See "Ankle sprain in adults: Evaluation and diagnosis", section on 'Special tests'.)

●(See "Ankle sprain in adults: Evaluation and diagnosis", section on 'Grading'.)

●(See "Ankle sprain in adults: Management", section on 'Treatment'.)

Anterior

Talus fractures — Fractures of the talus typically arise from a high-energy injury (eg, motor vehicle collision or fall from a height) that applies axial loading of the plantar- or dorsiflexed ankle. The subset of lateral process talus fractures, most often seen in snowboarders, frequently occurs during a hard landing after a jump and involves an uncontrolled axial load, often when the ankle is dorsiflexed and slightly rotated. (See "Talus fractures", section on 'Mechanism of injury'.)

The patient with a talus fracture often presents with pain and swelling around the ankle and difficulty with weight bearing following trauma. Pain may be described as deep in the ankle. Ankle range of motion is often limited. The symptoms and signs associated with lateral process fractures of the talus, described in snowboarders, are similar to an ankle sprain, and, therefore, these injuries can be misdiagnosed. (See "Talus fractures", section on 'History and examination findings'.)

Typically, patients with a talus fracture manifest tenderness to palpation at and below the ankle. Tenderness may be focal or generalized. Palpation should include the talar head and neck (just distal and anterior to the ankle joint) (picture 9), the talar body (just anterior, inferior, and posterior to each malleolus) (picture 10 and picture 11 and picture 12), the talar dome (on the anterior joint line with the foot and ankle plantar-flexed) (picture 13), and the posterior talus (deep palpation just anterior to the Achilles tendon from both the medial and lateral aspect). Depending upon the location of the fracture, it may be difficult to reproduce pain with palpation. An ankle effusion will be present. (See "Talus fractures", section on 'History and examination findings'.)

The diagnosis of a talus fracture is made by radiographic imaging. The mortise view is an essential part of the three-view ankle radiographs series because with this view the often injured lateral dome of the talus is not obscured by the fibula. Computed tomography may be needed to make a definitive diagnosis in some cases and should be obtained if clinical suspicion for a fracture remains high in the face of negative plain radiographs. The management of talus fractures is discussed separately. (See "Talus fractures", section on 'Diagnosis' and "Talus fractures", section on 'Talus fracture types: Special aspects of presentation and management'.)

Syndesmotic ankle sprain (high ankle sprain) — A high ankle sprain is an injury to the ligaments of the distal tibiofibular syndesmosis. The most common mechanism of injury is external rotation to an ankle that is dorsiflexed. These injuries typically involve contact. Patients often present with difficulty bearing weight, edema over the anterior ankle, which may extend laterally, and tenderness to palpation along the interosseous membrane and transverse tibiofibular ligaments. Syndesmotic ankle injuries contribute to chronic ankle instability and are more likely to cause recurrent ankle sprains, especially if there is an associated deep deltoid ligament injury.

The assessment, grading, and management of syndesmotic ankle injuries are discussed separately. (See "Syndesmotic ankle injury (high ankle sprain)".)

Posterior

Achilles tendon rupture — Achilles tendon rupture occurs rarely in children and young adolescents. With rupture, patients often have preceding trauma to the tendon followed by severe pain at the back of the ankle and have difficulty bearing weight. Some also describe a "pop." However, the absence of pain does not rule out rupture. Physical examination may show a gap in the tendon contour compared with the unaffected side and a proximal nodule in the calf. Also, when the patient is prone, the foot on the affected side is neutral or dorsiflexed rather than plantar-flexed (Matles sign). The calf squeeze or Thompson test (picture 14) demonstrates no plantar flexion when the gastrocnemius muscle is squeezed. The diagnosis is usually made clinically, but confirmatory testing such as diagnostic ultrasound or MRI is useful when the Thompson test is negative but clinical suspicion remains high. (See "Achilles tendinopathy and tendon rupture", section on 'Physical examination'.)

The treatment of Achilles tendon rupture is discussed separately. (See "Achilles tendinopathy and tendon rupture", section on 'Treatment'.)

Posterior process talus fractures — Fractures of the posterior process of the talus may occur from one of two mechanisms. Forceful plantarflexion may drive the posterior process against the posterior tibia or cause it to become caught between the calcaneus and the posterior tibia. Alternatively, the posterior process may be avulsed by the pull of the posterior talofibular ligament during extreme dorsiflexion of the ankle.

Patients with a fracture of the posterior process of the talus typically present with posterior ankle pain and swelling with ecchymosis. They may be able to bear weight but typically have an antalgic gait. Tenderness with deep palpation of the posterior ankle is present either medially (picture 12), laterally (picture 10), or both. Plain ankle radiographs, particularly the lateral view, may show a posterior process fracture (image 5). However, plain radiographs may suggest the presence of an os trigonum, and it can be difficult to distinguish between a fracture and an ossicle. Comparison with the other ankle using plain radiographs, or a CT scan, may be needed to make the diagnosis. The management of posterior process talus fractures is provided separately. (See "Talus fractures", section on 'Posterior process (trigonum) fractures'.)

CHRONIC CONDITIONS

Lateral

Osteochondritis dissecans (anterior lateral talus) — Osteochondritis dissecans (OCD) is a condition in which a segment of articular cartilage, with its underlying subchondral bone, gradually separates from the surrounding osteocartilaginous tissue. The pain may develop and increase over a period of several months. Less commonly, acute injury with inversion of the ankle is an inciting event. Lesions of the anterior lateral talus are associated with ankle dorsiflexion. Symptoms include pain, stiffness, weakness, mechanical sensation (eg, popping, clicking, or locking), and occasionally a loose body sensation (ie, of something floating around) in the ankle. Pain may be produced by palpation over the anterior lateral or posterior medial talus. (See "Osteochondritis dissecans (OCD): Clinical manifestations, evaluation, and diagnosis", section on 'Clinical presentation'.)

The diagnosis of OCD typically requires imaging. (See "Osteochondritis dissecans (OCD): Clinical manifestations, evaluation, and diagnosis", section on 'Diagnosis and classification'.).

The management of OCD is discussed separately. (See "Management of osteochondritis dissecans (OCD)".)

Sinus tarsi syndrome — The sinus tarsi or talocalcaneal sulcus is the space between the lateral neck of the talus and the superior aspect of the anterior calcaneus. It runs an oblique course between the talus and calcaneus from lateral to medial coursing anterior to posterior. It is a funnel-shaped area located anterior and inferior to the lateral malleolus (ie, the soft spot beneath the anterior talofibular ligament [ATFL]) (figure 3) and is the lateral extension of the tarsal canal. Sinus tarsi syndrome (STS) is synovitis of the lateral aspect of the anterior subtalar joint. With inversion injuries of the ankle, the extrinsic ligaments (ATFL and calcaneofibular ligament) are the first to be injured. If the inversion is severe or recurrent, the interosseous ligaments of the sinus tarsi also are affected, resulting in subtalar functional instability. (See "Evaluation and diagnosis of common causes of hindfoot pain in adults", section on 'Sinus tarsi syndrome'.)

Patients who have STS usually present soon after the injury with diffuse swelling and pain over the lateral ankle and difficulty bearing weight. On examination, the patient has pain and point tenderness deep to the ATFL. Pain can be provoked by even minor pressure over the lateral opening of the sinus tarsi. The pain is reproducible with supination/inversion and adduction of the hindfoot of the affected side. In the acute phase, STS is not distinguishable from an ankle sprain and is treated as such. However, as the swelling and pain resolve, patients complain of functional instability of the involved ankle and diffuse pain on the lateral side of the foot, particularly when walking on uneven surfaces. (See "Evaluation and diagnosis of common causes of hindfoot pain in adults", section on 'Sinus tarsi syndrome' and "Ankle sprain in adults: Management", section on 'Treatment'.)

If ankle instability is detected on examination, other diagnoses should be considered (eg, ligamentous injury). Patients with chronic STS may develop peroneal spasm with associated pes planus as they try to compensate for subtalar pain. (See "Evaluation and diagnosis of common causes of hindfoot pain in adults", section on 'Sinus tarsi syndrome'.)

The history and physical examination provide the diagnosis. Patients with ankle instability warrant appropriate imaging (eg, plain radiographs with additional imaging dependent upon findings). The treatment of STS is discussed separately. (See "Evaluation and diagnosis of common causes of hindfoot pain in adults", section on 'Sinus tarsi syndrome'.)

Peroneal injuries — The two main tendons that run along the lateral ankle are the peroneus (or fibularis) longus (picture 3 and picture 1) and peroneus (or fibularis) brevis (picture 4 and picture 1). The peroneal muscles that give rise to these tendons reside in the lateral compartment of the leg and are the primary muscles performing foot eversion (picture 1 and figure 11). Injuries to the peroneal tendon include synovitis of the tendon sheath, longitudinal tears, and retinacular attenuation with peroneal tendon subluxation or dislocation. (See "Non-Achilles ankle tendinopathy", section on 'Lateral ankle tendinopathy'.)

Although uncommon in children and young adolescents, peroneal tendon injuries should be considered in any patient who presents with acute or chronic lateral ankle inversion sprains with or without associated swelling or instability. Peroneal tendinitis usually is associated with insufficient rehabilitation of lateral ankle sprains. It also can be precipitated by changes in footwear, training regimen, or playing surface or as a result of repetitive or prolonged activity (eg, endurance sports, such as marathon running). Patients with peroneal tendinitis may complain of pain, swelling, and warmth in the region of the peroneal tendons. The pain is worsened by passive inversion with plantar flexion or active eversion with dorsiflexion of the foot. The complaints are present for less than six weeks in acute tendinitis and for greater than six weeks in chronic tendinitis. The diagnosis of peroneal tendinitis can usually be made on the basis of the history and examination, without advanced imaging. (See "Non-Achilles ankle tendinopathy", section on 'Clinical presentation and physical examination' and "Non-Achilles ankle tendinopathy", section on 'Diagnosis'.)

Treatment of peroneal tendinitis is discussed separately. (See "Non-Achilles ankle tendinopathy", section on 'Treatment'.)

Lateral ankle impingement — Lateral ankle impingement describes the clinical scenarios that cause pinching of the soft tissues, synovium, accessory ossicles/ligaments on the lateral side of the ankle between the talus, fibula, and the calcaneus [1]. Talofibular impingement can occur when there is increased anterior talar translation causing its impact into the distal fibula. In patients with chronic ankle instability, this repetitive trauma can result in osteochondral lesions of the anterior lateral talar dome and thickening of the relatively common accessory anterior inferior tibiofibular ligament (Bassett's ligament). Impingement between the calcaneus and the distal fibula/lateral talus can occur with excessive ankle eversion in clinical diagnoses such as posterior tibialis dysfunction, peroneal spasm, and hypermobile pes planus. While soft tissues and synovium are the most common structures to impinge, an accessory os subfibulare can also occupy space in the location of lateral ankle impingement.

Patients with lateral ankle impingement will complain of lateral ankle pain and possibly mild swelling that is often worsened with prolonged standing/walking. Symptoms may be worsened especially in those with hypermobile pes planus who are wearing shoes with inadequate arch support or heel counter and fail to tie their shoes appropriately. Symptoms of painful mechanical sensations should increase suspicion for osteochondral lesions in the talar dome.

Radiographs should be considered as a first-line screening to assess for osteochondral lesions, accessory ossicles, tarsal coalitions, and other anatomic reasons for impingement [1]. MRI may be warranted in atypical cases or in those who fail to improve with adequate conservative management.

Conservative management will include adequate activity modification, appropriate shoe wear, ankle and foot intrinsic strengthening, calf stretching, and proprioception training. Surgical consultation should be considered if there is inadequate improvement after two to three months or if there is a correctable anatomic etiology identified on imaging.

Os peroneum — The os peroneum is present within the substance of the peroneus longus in 20 percent of feet (picture 5) [2]. These ossicles typically are located plantar to the cuboid bone, lateral to the calcaneus, or at the calcaneocuboid articulation [2]. The presence of an os peroneum, especially with hypertrophy of the peroneal tubercle, predisposes to the development of peroneus longus stenosing tenosynovitis in the region of the cuboid tunnel [3].

Lateral ankle and/or foot pain is the most common symptom [2]. Examination demonstrates pain with palpation of the region of the lateral plantar cuboid or near the calcaneocuboid articulation (figure 12) and thickening and tenderness of the peroneus longus and brevis tendon sheath. Pain at the os typically is exacerbated in the heel-rise phase of gait, by resisted plantar flexion of the first ray (ie, the first metatarsal and the two phalanges of the great toe), and by the varus inversion stress test [2]. The varus inversion stress test is performed by placing the symptomatic foot in an inverted, supinated, and adducted position similar to testing the integrity of the ATFL [2]. In addition, patients may complain of pain or the sensation of stepping on a pebble with forced foot eversion [2].

Os peroneum are demonstrated on the radiographs that are recommended in the evaluation of patients with lateral ankle pain (eg, anteroposterior [AP], lateral, and mortise views of the ankle), and AP and oblique views of the foot. Os peroneum usually are seen best on the oblique view of the foot [2]. Acute fracture or diastasis of a multipartite os peroneum, callus formation involving the os peroneum, or proximal migration of the os peroneum suggests peroneus longus tendon pathology [2]. (See 'Peroneal injuries' above.)

Treatment for pain in the region of the os peroneum includes rest, ice packs, and a brief course of nonsteroidal anti-inflammatory drugs (NSAIDs) for pain. Immobilization of the lower leg may be necessary for patients with severe symptoms. As symptoms resolve, the patient should start a well-designed and controlled rehabilitation program of stretching and strengthening as for patients with peroneal tendinitis (table 1 and picture 15). (See "Non-Achilles ankle tendinopathy", section on 'Treatment'.)

Exertional compartment syndrome — Chronic exertional compartment syndrome (CECS) refers to exercise-induced gradually increasing pain in a specific muscle region (usually the lower leg) during physical exertion. Potential lateral compartment muscles that may present with lateral ankle pain consist of the peroneus longus and brevis muscles (figure 13). Affected patients report lateral lower leg cramping pain that begins within several minutes of the inciting activity (typically running), increases steadily with continued exertion, may be associated with altered sensation on the dorsum of the foot (superficial peroneal nerve), and resolves with rest within minutes to hours. It often recurs despite extended periods of rest (weeks/month). Patients with CECS are typically asymptomatic at rest and during activities of daily living. Physical examination is often unremarkable at rest but, when the patient exercised to the point of symptoms, may show tenderness or tenseness of the affected muscle compartment. A definitive diagnosis is made by measuring compartment pressures at rest and following exercise. The clinical features, diagnosis, and management of CECS are discussed in greater detail separately. (See "Chronic exertional compartment syndrome", section on 'Diagnosis' and "Chronic exertional compartment syndrome", section on 'Management'.)

Tarsal coalition — Tarsal coalition is an abnormal connection (fibrous, cartilaginous, or osseous) between two or more bones in the mid/rear foot (most commonly calcaneonavicular or talocalcaneal (figure 14)) that commonly presents between the age of 8 and 12 years. Many patients are asymptomatic, but tarsal coalition can be associated with lateral ankle pain and recurrent ankle sprains. Physical examination findings include rigid flat foot, hindfoot valgus, loss of subtalar motion, and limited painful passive ankle inversion. The diagnosis of tarsal coalition requires appropriate imaging. Foot radiographs with special views are the first-line imaging of choice, as discussed separately. (See "Forefoot and midfoot pain in the active child or skeletally immature adolescent: Overview of causes", section on 'Tarsal coalition'.)

Medial

Flexor hallucis longus injuries — The posterior medial ankle contains three tendons: the posterior tibial, flexor digitorum longus, and the flexor hallucis longus (FHL) (picture 6). Of these tendons, only the FHL passes through a discrete fibro-osseous tunnel, similar to the first wrist extensor compartment. Because of this anatomy, the FHL tendon is prone to developing a tenosynovitis similar to de Quervain tenosynovitis of the abductor pollicis longus and extensor pollicis brevis, ie, characterized by noninflammatory thickening of the tendon and the tunnel (or sheath) through which it passes. Other FHL injuries include swelling, triggering, partial tears, and complete ruptures. (See "de Quervain tendinopathy" and "Non-Achilles ankle tendinopathy", section on 'Medial ankle tendinopathy'.)

FHL tendinitis is uncommon in children and young adolescents. It most frequently affects classic ballet dancers but also occurs in runners, soccer players, martial arts athletes, and other athletes. The symptoms of FHL stenosing tenosynovitis typically begin insidiously and may be present for several months before coming to medical attention. Patients complain of pain and tenderness at the posteromedial ankle (figure 12). The pain may radiate distally along the medial arch and is exacerbated by weight-bearing or athletic activity. (See "Non-Achilles ankle tendinopathy", section on 'Clinical presentation and physical examination'.)

Examination reveals tenderness and, occasionally, crepitation over the sheath of the FHL tendon behind the medial malleolus (figure 12). Passive and/or active ankle range of motion is painful, and crepitus or triggering of the hallux (ie, locking of the toe in a certain position, caused by "catching" of the tendon, that is relieved spontaneously) may be present. The plantar flexion test should be performed to evaluate for posterior impingement, which if present suggests associated os trigonum syndrome. In this test, symptoms are reproduced or increased by resisted plantar flexion because the FHL tendon pushes against the accessory ossicle as it passes over the bone.

The diagnosis is made based upon clinical findings. Plain radiographs are typically performed to exclude bony abnormalities and should include AP, lateral, and mortise views and a lateral ankle view with the foot in full equinus (eg, fully flexed and inverted). If the patient is a ballet dancer, it is helpful to obtain a lateral ankle radiograph with the patient wearing a pointe shoe. MRI can be helpful to evaluate for tenosynovitis of the FHL, posterior impingement, and injury to the os trigonum or sustentaculum tali. (See "Non-Achilles ankle tendinopathy", section on 'Diagnosis'.)

The treatment of FHL tendinitis is discussed separately. (See "Non-Achilles ankle tendinopathy", section on 'Flexor hallucis longus tendinopathy'.)

Os tibiale externum (accessory navicular) — The os tibiale externum, also known as the accessory navicular, os naviculare, naviculare secundarium, bifurcated hallux, or pre-hallux, is an accessory bone that is present in 2 to 21 percent of the population [4,5]. It is adjacent to the tuberosity of the navicular and is classified into three different types [4,5]. In type I (30 percent), the ossicle is located in the posterior tibialis tendon and is relatively small (less than 3 mm). The most common, type II (55 percent), is larger, often heart shaped, and has a cartilaginous synchondrosis to the navicular. The type III or cornuate navicular (15 percent) has a bony attachment to the navicular. While most are asymptomatic, some will become painful with repetitive pressure on the medial foot (hockey and soccer players, skaters, skiers), with excessive tension from rearfoot pronation (runners with pes planus), or with acute eversion injury.

Radiographs are sufficient for classification of the ossicle type. In cases with severe pain or prolonged recovery despite adequate treatment, MRI is useful, especially in type II, to determine if there is an injury to the cartilaginous synchondrosis, which requires longer conservative management. MRI will also help to define the anatomy of the posterior tibialis tendon and evaluate for other possible diagnoses that mimic this injury, such as tarsal tunnel syndrome or rupture of the posterior tibialis tendon.

The diagnosis and treatment are discussed in further detail separately. (See "Forefoot and midfoot pain in the active child or skeletally immature adolescent: Overview of causes", section on 'Pes cavus (high arch)'.)

Posterior tibialis tendinitis — The posterior tibialis muscle inverts and plantar flexes the foot and supports the medial longitudinal arch (picture 7 and figure 15). Patients with posterior tibialis tendinopathy typically complain of pain around the posteromedial ankle. Swelling may be present along the course of the tendon, particularly several centimeters proximal to its insertion on the navicular. However, as the condition progresses, partial tearing of the tendon or avulsion from its insertion on the navicular can occur, and the longitudinal arch may drop resulting in a "flat foot" (type III pes planus) (see "Forefoot and midfoot pain in the active child or skeletally immature adolescent: Overview of causes", section on 'Type III'). This collapse causes midfoot rotation and impingement of lateral structures. The patient may then complain of lateral ankle pain and a gradual "turning out" of the foot. In most cases of posterior tibialis tendinopathy, pain increases gradually over weeks and patients do not recall a traumatic event. Some patients may recall a twisting type of injury, such as stepping off a curb or stepping into a hole, and, in such cases, the condition is often misdiagnosed as a medial ankle sprain. Tibialis posterior tendinitis can also follow overuse during high-impact sports such as basketball, tennis, or soccer. (See "Non-Achilles ankle tendinopathy", section on 'Anatomy' and "Non-Achilles ankle tendinopathy", section on 'Clinical presentation and physical examination'.)

The clinical manifestations, diagnosis, and treatment of tibialis posterior tendinitis are discussed separately. (See "Non-Achilles ankle tendinopathy", section on 'Medial ankle tendinopathy'.)

Tarsal tunnel syndrome — The tarsal tunnel is a bony canal that runs below the medial malleolus and through which travel the tibialis posterior, flexor hallucis, and flexor digitorum tendons, posterior tibial artery and vein, and tibial nerve (figure 6). Tarsal tunnel syndrome often affects individuals with a prior injury to the medial ankle or a markedly pronated gait. When the arch of the foot collapses and the foot pronates excessively, the bones of the tibiotalar or subtalar joint may move and even sublux, and this too, can cause compression of the structures running through the tarsal tunnel. Pressure on the tibial nerve causes neuropathic pain that typically radiates to the heel and plantar surface of the forefoot. This is classic tarsal tunnel syndrome. Over time, compression of the tarsal tunnel can also result in injury of the posterior tibialis or flexor hallucis tendons with findings of tendinitis. (See "Non-Achilles ankle tendinopathy", section on 'Medial ankle tendinopathy'.)

Osteochondritis dissecans (posterior medial talus) — OCD is a condition in which a segment of articular cartilage, with its underlying subchondral bone, gradually separates from the surrounding osteocartilaginous tissue. The pain may develop and increase over the period of several months in affected patients. Less commonly, acute injury with inversion of the ankle is an inciting event. Symptoms include pain, stiffness, weakness, mechanical sensation (eg, popping, clicking, or locking), and occasionally a loose body sensation (ie, of something floating around) in the ankle. No pathognomonic signs exist, but pain may be produced by palpation over the posterior medial talus with the foot in dorsiflexion. (See "Osteochondritis dissecans (OCD): Clinical manifestations, evaluation, and diagnosis", section on 'Talus'.)

The diagnosis of OCD typically requires imaging (image 1). (See "Osteochondritis dissecans (OCD): Clinical manifestations, evaluation, and diagnosis", section on 'Diagnosis and classification'.)

The management of OCD is discussed separately. (See "Management of osteochondritis dissecans (OCD)".)

Navicular stress fracture — Stress fractures of the navicular bone are considered high risk because of their propensity for nonunion. They have been reported in runners, pole vaulters, tennis players, and gymnasts. Repetitive loading of the medial column of the foot drives the head of the talus into the navicular, resulting in fracture in the middle one-third of the bone, an area of relative hypovascularity. (See "Overview of stress fractures", section on 'High-risk sites'.)

Patients will often complain of diffuse midfoot pain, with or without discrete tenderness over the dorsal aspect of the navicular on physical examination, but on occasion will complain of medial ankle pain. Athletes of all ages, especially runners who are overtraining, are at risk.

This diagnosis and treatment of stress fractures, including navicular stress fractures, are discussed separately. (See "Overview of stress fractures" and "Foot and ankle pain in the active child or skeletally immature adolescent: Evaluation".)

Anterior

Tibialis anterior tendinitis — The anterior tibialis muscle originates along the proximal two-thirds of the lateral tibia and inserts onto the plantar aspect of the base of the first metatarsal and first cuneiform (picture 8). The muscle functions as the main dorsiflexor of the foot but also plays a role in foot adduction and inversion. (See "Non-Achilles ankle tendinopathy", section on 'Anterior ankle tendinopathy'.)

Tibialis anterior tendinitis is an uncommon injury that occurs in athletes who wear a fixed boot (eg, skiers, skaters), runners (especially downhill running), and "weekend athletes," who do not maintain a consistent level of training. The most common etiology is mechanical pressure over the tendon from tight shoelaces, eyelets on the shoes, or a tight fixed boot. Tendinitis is also associated with running on hard surfaces, over striding, and excessive pronation of the foot. Excessive pronation elongates the anterior tibial tendon, which can predispose to tenosynovitis. (See "Non-Achilles ankle tendinopathy", section on 'Clinical presentation and physical exam'.)

Patients who have acute tibialis anterior tendinitis present with pain along the course of the tendon, usually along and over the anteromedial ankle. The pain is precipitated by activity and improves with rest. Patients should be questioned about change in the amount and type of activity, activity level, activity surface, and footwear, because change in any of these variables can cause tibialis anterior tendinitis. Physical examination reveals pain with either passive plantar flexion or active dorsiflexion. The area of tenderness and swelling along the tibialis anterior muscle is best appreciated with the foot actively dorsiflexed. Evaluation of the foot for biomechanical imbalance (ie, asymmetry in flexibility or strength between agonist and antagonist muscle groups) also should be performed. (See "Non-Achilles ankle tendinopathy", section on 'Clinical presentation and physical exam'.)

The diagnosis of tibialis anterior tendinitis is typically made based upon history and physical examination. Plain radiographs of the ankle are indicated for patients with acute trauma and focal bony tenderness, deformity, or difficulty bearing weight. (See "Non-Achilles ankle tendinopathy", section on 'Diagnosis'.)

The treatment of tibialis anterior tendinitis is discussed separately. (See "Non-Achilles ankle tendinopathy", section on 'Treatment'.)

Osteochondritis dissecans (anterior lateral talus) — OCD is a condition in which a segment of articular cartilage, with its underlying subchondral bone, gradually separates from the surrounding osteocartilaginous tissue. The pain may develop and increase over the period of several months in affected patients. Less commonly, acute injury with inversion of the ankle is an inciting event. Symptoms include pain, stiffness, weakness, mechanical sensation (eg, popping, clicking, or locking), and occasionally, a loose body sensation (ie, of something floating around) in the ankle. No pathognomonic signs exist, but pain may be produced by palpation over the anterior lateral and posterior medial talus with the foot in plantar flexion. (See "Osteochondritis dissecans (OCD): Clinical manifestations, evaluation, and diagnosis", section on 'Talus'.)

The diagnosis of OCD typically requires imaging. (See "Osteochondritis dissecans (OCD): Clinical manifestations, evaluation, and diagnosis", section on 'Diagnosis and classification'.)

The management of OCD is discussed separately. (See "Management of osteochondritis dissecans (OCD)".)

Exertional compartment syndrome — CECS refers to exercise-induced, gradually increasing pain in a specific muscle region (usually the lower leg) during physical exertion. Potential anterior compartment muscles that may present with anterior ankle pain consist of the tibialis anterior, extensor digitorum longus, and extensor hallucis longus muscles (figure 13). Affected patients report anterior shin cramping pain that begins within several minutes of the inciting activity (typically running), increases steadily with continued exertion, may be associated with altered sensation on the dorsum of the first webspace of the foot (deep peroneal nerve), and resolves with rest within minutes to hours. It often recurs despite extended periods of rest (weeks/month). Patients with CECS are typically asymptomatic at rest and during activities of daily living. Physical examination is often unremarkable at rest but, when the patient exercised to the point of symptoms, may show tenderness or tenseness of the affected muscle compartment. A definitive diagnosis is made by measuring compartment pressures. The clinical features, diagnosis, and management of CECS are discussed in greater detail separately. (See "Chronic exertional compartment syndrome", section on 'Diagnosis' and "Chronic exertional compartment syndrome", section on 'Management'.)

Anterior impingement — Spurring off the anterior distal tibia or the anterior superior talus can produce impingement at the anterior ankle, causing pain around the proximal talus. Such pain can also occur without spurring. In either situation, sports or other activities that cause repeated stressful dorsiflexion of the foot may contribute to the injury. Examples include basketball, volleyball, ballet, hiking, or climbing ladders. Anterior ankle swelling or an abnormal contour of the anterior ankle and tibiotalar articulation may be apparent. Ankle dorsiflexion may be limited and localized tenderness present. Standard radiographs usually confirm the diagnosis, but sometimes oblique views are needed. Management is discussed separately. (See "Evaluation and diagnosis of common causes of hindfoot pain in adults", section on 'Anterior and posterior ankle impingement'.)

Posterior

Achilles tendinitis — Patients with Achilles tendinitis describe pain in the distal tendon about 2 cm proximal to its insertion on the calcaneus (figure 9). It is often associated with inflexibility in the gastrocnemius/soleus complex or a remote ankle injury with inadequate rehabilitation. Running or jumping will classically increase irritation. It is more common in skeletally mature patients and is an unusual condition in children and young adolescents. Pain at the insertion of the Achilles tendon at this age may be an important marker for inflammatory enthesitis (eg, juvenile idiopathic arthritis) but also can be seen in some cases of calcaneal apophysitis. (See "Oligoarticular juvenile idiopathic arthritis", section on 'Clinical presentation' and "Heel pain in the active child or skeletally immature adolescent: Overview of causes", section on 'Calcaneal apophysitis (Sever disease)'.)

The treatment of Achilles tendonitis is discussed detail separately. (See "Achilles tendinopathy and tendon rupture", section on 'Acute tendinopathy'.)

Os trigonum syndrome (posterior ankle impingement) — The os trigonum is the persistence of the lateral ossification center on the posterior aspect of the talus after skeletal maturation [6]. The groove for the flexor hallucis longus (FHL) tendon on the posterior aspect of the talus has an elongated lateral wall called Stieda process. Between the ages of 8 and 11 years, separate ossification centers appear and usually rapidly fuse with the medial and lateral tubercles of the groove. Persistence of the lateral ossification center occurs in approximately 13 percent of the population; it occurs bilaterally in 50 percent of patients [7]. Acquired os trigonum syndrome can result from a fracture that fails to reunite (usually sustained in a hyper plantar flexion injury).

Os trigonum is seldom symptomatic; it is a normal structure and should not deter a career in dance or other athletic endeavor. The os trigonum syndrome results when the os trigonum causes posterolateral ankle pain. Os trigonum syndrome may be caused by a free accessory bone or a bone fused to the talus at Stieda process [7]. Although the pathogenesis of pain is not known, the most accepted theory proposes that the os becomes impinged between the calcaneus and the posterior lip of the tibia during extreme plantar flexion. Os trigonum syndrome is considered part of the posterior impingement syndrome, which can involve the os trigonum, Stieda process, or the FHL tendon.

Patients with os trigonum syndrome describe pain in the posterior lateral aspect of the ankle; symptoms may be exacerbated when walking downhill. Tenderness is present at the posterolateral aspect of the ankle [6]. Pain is accentuated by squatting, resisted plantar flexion, or dorsiflexion of the great toe because these maneuvers cause the flexor hallucis longus to push against the ossicle as the FHL passes over the talus. Plantar flexion of the foot with axial loading to the heel reproduces the symptoms. The plantar flexion sign is the key to diagnosis because it distinguishes posterior impingement from the other causes of posterior ankle pain (eg, Achilles tendinitis, bursitis, Haglund deformity).

Plain radiographs (lateral ankle and lateral ankle in plantar flexion) can demonstrate the presence of the os or Stieda process [6]. Bone scan is not necessary for diagnosis but can be helpful to evaluate the presence of fracture or cortical edema. Similarly, MRI is not necessary for diagnosis but can help to determine the presence of inflammation in the posterior capsule, FHL, bursa, or the os trigonum.

Modified activity and pain control with ice packs and/or NSAIDs can provide symptomatic relief [6-8]. Improvement of rearfoot strength and proprioception may prevent recurrence. Patients with recalcitrant pain warrant referral to a foot and ankle surgeon. Operative management usually includes excision of both the os trigonum and Stieda process and adjacent release of the FHL [7].

Talar stress fractures — Stress fractures of the talus are rare events in children and young adolescents. Stress fractures of the lateral process of the talus are seen in runners who supinate (invert) their feet. Stress fractures at the neck of the talus also can be associated with calcaneonavicular coalition. Patients with stress fractures of the talus complain of having chronic rearfoot pain with activity. They also may complain of an ankle sprain that has failed to improve despite appropriate treatment and rehabilitation. The examination may show decreased subtalar movement and a discrete area of tenderness over the talus. (See "Overview of stress fractures" and "Overview of stress fractures", section on 'Diagnosis'.)

Orthopedic consultation should be obtained for children with stress fractures of the talus because the long-term prognosis is poor (eg, failure to heal, development of subsequent arthritis), even with appropriate therapy. Treatment of stress fractures is discussed separately. (See "Overview of stress fractures", section on 'Treatment concepts'.)

Osteochondritis dissecans (posterior medial talus) — OCD is a condition in which a segment of articular cartilage, with its underlying subchondral bone, gradually separates from the surrounding osteocartilaginous tissue. The pain may develop and increase over the period of several months in affected patients. Less commonly, acute injury with inversion of the ankle is an inciting event. Symptoms include pain, stiffness, weakness, mechanical sensation (eg, popping, clicking, or locking), and occasionally a loose body sensation (ie, of something floating around) in the ankle. No pathognomonic signs exist, but pain may be produced by palpation over the posterior medial talus with the foot in dorsiflexion. (See "Osteochondritis dissecans (OCD): Clinical manifestations, evaluation, and diagnosis", section on 'Talus'.)

The diagnosis of OCD typically requires imaging. (See "Osteochondritis dissecans (OCD): Clinical manifestations, evaluation, and diagnosis", section on 'Diagnosis and classification'.)

The management of OCD is discussed separately. (See "Osteochondritis dissecans (OCD): Clinical manifestations, evaluation, and diagnosis", section on 'Diagnosis and classification'.)

Achilles tendon enthesitis — Posterior ankle pain may arise from enthesitis (painful tendon or ligament insertions) at the insertion of the Achilles tendon on the calcaneus, which may be a manifestation of reactive arthritis or rheumatologic disease. (See "Heel pain in the active child or skeletally immature adolescent: Overview of causes", section on 'Inflammatory enthesitis'.)

Exertional compartment syndrome — CECS refers to exercise-induced gradually increasing pain in a specific muscle region (usually the lower leg) during physical exertion. Potential posterior compartment muscles that may present with posterior ankle pain primarily consist of the deep posterior muscles: tibialis posterior, flexor digitorum longus, and flexor hallucis longus (figure 13). Affected patients report deep posterior leg cramping pain that begins within several minutes of the inciting activity (typically running), increases steadily with continued exertion, with altered sensation on the plantar foot (tibial nerve), and resolves with rest within minutes to hours. It often recurs despite extended periods of rest (weeks/month). Patients with CECS are typically asymptomatic at rest and during activities of daily living. Physical examination is often unremarkable at rest but, when the patient is exercised to the point of symptoms, may show tenderness or tenseness of the affected muscle compartment. A definitive diagnosis is made by measuring compartment pressures. The clinical features, diagnosis, and management of CECS are discussed in greater detail separately. (See "Chronic exertional compartment syndrome", section on 'Diagnosis' and "Chronic exertional compartment syndrome", section on 'Management'.)

DIFFUSE OR NONSPECIFIC LOCATION

Osteomyelitis — Hematogenous osteomyelitis can occur in the distal tibia and is associated with fever, swelling, and tenderness at the site of infection. Although the clinical presentation of osteomyelitis can be nonspecific, signs of infection (ie, fever, localized erythema, induration, swelling, and warmth and/or elevated erythrocyte sedimentation rate and C-reactive protein levels) may be present. (See "Hematogenous osteomyelitis in children: Clinical features and complications".)

The diagnosis of osteomyelitis is supported by a combination of the following (see "Hematogenous osteomyelitis in children: Evaluation and diagnosis", section on 'Diagnostic approach'):

●Clinical features suggestive of bone infection (constitutional symptoms, focal symptoms and signs of bone inflammation, limitation of function, elevated erythrocyte sedimentation rate, and/or C-reactive protein) (see "Hematogenous osteomyelitis in children: Evaluation and diagnosis", section on 'Clinical suspicion' and "Hematogenous osteomyelitis in children: Evaluation and diagnosis", section on 'Blood tests')

●An imaging study with abnormalities characteristic of osteomyelitis (table 2) (see "Hematogenous osteomyelitis in children: Evaluation and diagnosis", section on 'Radiographs' and "Hematogenous osteomyelitis in children: Evaluation and diagnosis", section on 'Advanced imaging')

●A positive microbiologic or histopathologic specimen (see "Hematogenous osteomyelitis in children: Evaluation and diagnosis", section on 'Microbiology' and "Hematogenous osteomyelitis in children: Evaluation and diagnosis", section on 'Histopathology')

●A response to empiric antimicrobial therapy (see "Hematogenous osteomyelitis in children: Evaluation and diagnosis", section on 'Response to empiric therapy')

Consultation with a pediatric orthopedic surgeon and radiologist is warranted when osteomyelitis is suspected to guide the diagnostic approach and treatment. The evaluation and treatment of osteomyelitis is discussed in detail separately. (See "Hematogenous osteomyelitis in children: Evaluation and diagnosis" and "Hematogenous osteomyelitis in children: Management".)

Infectious arthritis — Infectious arthritis is less common in the ankle than at other sites (eg, knee or hip) but remains an important cause of ankle swelling and pain.

Bacterial arthritis of the ankle is suggested by constitutional symptoms in addition to swelling, tenderness, and limited mobility of the affected joint. Physical examination demonstrates localized swelling, erythema, warmth, and limited range of motion. Patients typically cannot ambulate. (See "Bacterial arthritis: Clinical features and diagnosis in infants and children", section on 'Clinical features'.)

The diagnosis of bacterial arthritis is suggested by elevation of the white blood cell count, erythrocyte sedimentation rate, and/ or C-reactive protein. Plain radiographs may show a joint effusion or foci of osteomyelitis and excludes the presence of a fracture. Isolation of a bacterial pathogen from the synovial fluid (by culture or other diagnostic technique) confirms the diagnosis. Consultation with an orthopedic surgeon is warranted for irrigation and drainage. (See "Bacterial arthritis: Clinical features and diagnosis in infants and children", section on 'Diagnosis' and "Bacterial arthritis: Clinical features and diagnosis in infants and children", section on 'Indications for consultation'.)

In regions where Lyme disease is endemic, Lyme arthritis is an important consideration. Most patients with Lyme arthritis can ambulate, and fever or erythema is less common. Serologic testing for Lyme disease should be performed in patients with arthritis who reside in or have traveled to an endemic region and have a risk factor for tick exposure. The diagnosis and management of Lyme disease is discussed separately. (See "Treatment of Lyme disease", section on 'Arthritis' and "Diagnosis of Lyme disease".)

Tumor — Tumors, both benign and malignant, are rare causes of poorly localized ankle pain. The classic presentation is of night pain that is chronic and responsive to nonsteroidal anti-inflammatory drugs (eg, ibuprofen). Benign tumors that may arise in the bones of the ankle consist of osteoid osteomas, osteoblastomas, and chondromyxoid fibromas. Ewing sarcoma may rarely be seen in the calcaneus and may be difficult to distinguish from osteomyelitis. (See "Nonmalignant bone lesions in children and adolescents", section on 'Osteoid osteoma' and "Clinical presentation, staging, and prognostic factors of Ewing sarcoma".)

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Ankle sprain".)

INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5^th to 6^th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10^th to 12^th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.

Here are the patient education articles that are relevant to this topic. We encourage you to print or email these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)

●Basics topic (see "Patient education: Achilles tendon injury (The Basics)")

SUMMARY AND RECOMMENDATIONS

●Ankle pain in the young athlete can originate in the bones (eg, fractures) (figure 1 and figure 5), ligaments (eg, sprains) (figure 1 and figure 5), or muscles and tendons (tendinitis) (picture 1 and picture 2). History, physical examination, and, when indicated, plain radiographs are usually sufficient to make the correct diagnosis. (See 'Evaluation' above.)

●The acuity of the condition and careful localization of the site of tenderness can help to narrow the differential diagnosis. (See 'Localization of tenderness' above and 'Acute injuries' above and 'Chronic conditions' above.)

●Causes of lateral tenderness include:

•Acute pain (see 'Lateral' above)

-Fibular fracture (lateral malleolus)

-Anterior process fracture of calcaneus

-Ankle sprain (anterior to lateral malleolus) (figure 3)

•Chronic pain (see 'Lateral' above)

-Osteochondritis dissecans (OCD; anterior lateral talus)

-Sinus tarsi syndrome

-Peroneal injuries (picture 3 and picture 4 and picture 1)

-Os peroneum (picture 5)

-Tarsal coalition

●Causes of medial tenderness include:

•Acute pain (see 'Medial' above)

-Distal tibial fracture

-Deltoid ligament sprain (figure 2)

•Chronic pain (see 'Medial' above)

-Flexor hallucis longus injuries (picture 6)

-Os tibiale externum (accessory navicular bone)

-Posterior tibialis tendinitis (picture 7)

-Tarsal tunnel syndrome (figure 6)

-OCD (posterior medial talus (image 1))

-Navicular stress fracture

●Causes of anterior tenderness include:

•Acute pain (see 'Anterior' above)

-Talus fractures (rare in children)

-Syndesmotic ankle injury (high ankle sprain)

•Chronic pain (see 'Anterior' above)

-Tibialis anterior tendinitis (picture 8)

-OCD (anterior medial talus (image 1))

-Exertional compartment syndrome

-Anterior impingement

●Causes of posterior tenderness include:

•Acute pain (see 'Posterior' above)

-Achilles tendon rupture (figure 9)

-Posterior process of the talus fracture

•Chronic pain (see 'Posterior' above)

-Achilles tendinitis (figure 9)

-Os trigonum syndrome (posterior impingement syndrome) (image 2)

-Talar stress fracture

-Achilles tendon enthesitis from reactive or juvenile idiopathic arthritis

-Retrocalcaneal bursitis

-Exertional compartment syndrome (deep posterior)

●Osteomyelitis, infectious arthritis, or tumors arising in the bones of the ankle joint are associated with diffuse or nonspecific pain. (See 'Diffuse or nonspecific location' above.)