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Ankle Impingement Syndrome

• initial ankle injury

• abnormal osseous & soft tissue thickening in the subacute or chronic situation

• chronic ankle pain , painful limitation of ankle movement

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Ankle Impingement Syndrome

• Anterolateral Impingement

• Anterior Impingement

• Anteromedial Impingement

• Posterior Impingement

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Anatomy and Causes

secondary ossification center :

- 7-13 years, usually fuses within 1 year- large lateral talar process (Stieda process)- failure of fusion (os trigonum)

Posterior Impingement

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Anatomy and Causes

compression of soft tissue between posterior process of calcaneus and posterior tibia on plantar flexion of ankle

lateral posterior process of talus

os trigonum

chronic injury repetitive forced plantar flexion (usually)

acute injury avulsion fx of PTaF ligament, talar fx disruption of os trigonum

Posterior Impingement

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Lateral talar tubercle

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Os trigonum

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Clinical features posterior ankle pain

exacerbated by plantar flexion or dorsiflexion

posterior tenderness anterior to and not involving Axchilles tendon

palpable soft tissue thickening

Posterior Impingement

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Imaging features : Plain, CT, US prominent lateral talar process or os trigonum

fracture not evident on plain radiography

symptomatic os trigonum :↑ activitynegative scan excludes this diagnosis

Posterior Impingement

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Imaging features : MRI bone abnormality

bone marrow edema in lateral talar tubercle or os trigonumfracture line or fluid in synchondrosis (os trigonum fracture)

posterior capsular or ligament thickeninglow to intermediate SI on T2-WI

Synovitis posterior synovial recess of subtalar and tibiotalar joint FHL tendon sheath

Posterior Impingement

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Management

rehabilitative physiotherapy

imaging guided injection of steroid or local anesthetic into area of focal capsular thickening or os trigonum synchondrosis

surgical treatmentarthroscopic resection of osseous abnormaluty and soft tissue abnormality with washout of joint

Posterior Impingement

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Posterior ankle ligament

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Posterior Impingement

Prominent lateral talar tubercle focal thickening of posterior capsule

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Posterior Impingement

focal thickening of posterior capsule adjacent to posterior talus (T)

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Posterior Impingement

BM edema within os trigonum

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Posterior Impingement

focal thickening of posterior capsule

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Posterior Impingement

Prominent os trigonum BM edema in posterior talus

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Posterior Impingement

limited plantar flexion BM edema in posterior talus and adjacent bone fragment

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Posterior Impingement

BM edema in posterior talus and adjacent bone fragmentfragmentation of lateral talar tubercle

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Posterior Impingement

BM edema in posterior talusInflammation of posterior recess of tibiotalar and subtalar jointIncomplete fracture with osteosclerosis