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

Ankle Impingement Syndrome Anterolateral Impingement Anterior Impingement Anteromedial Impingement Posterior Impingement

Posterior Impingement 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 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

Lateral talar tubercle

Os trigonum

Posterior Impingement 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 Imaging features : Plain, CT, US prominent lateral talar process or os trigonum fracture not evident on plain radiography symptomatic os trigonum :↑ activity negative scan excludes this diagnosis

Posterior Impingement Imaging features : MRI bone abnormality bone marrow edema in lateral talar tubercle or os trigonum fracture line or fluid in synchondrosis (os trigonum fracture) posterior capsular or ligament thickening low to intermediate SI on T2-WI Synovitis posterior synovial recess of subtalar and tibiotalar joint FHL tendon sheath

Posterior Impingement Management rehabilitative physiotherapy imaging guided injection of steroid or local anesthetic into area of focal capsular thickening or os trigonum synchondrosis surgical treatment arthroscopic resection of osseous abnormaluty and soft tissue abnormality with washout of joint

Posterior ankle ligament

Posterior Impingement Prominent lateral talar tubercle focal thickening of posterior capsule

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

Posterior Impingement BM edema within os trigonum

Posterior Impingement focal thickening of posterior capsule

Posterior Impingement Prominent os trigonum BM edema in posterior talus

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

Posterior Impingement BM edema in posterior talus and adjacent bone fragment fragmentation of lateral talar tubercle

Posterior Impingement BM edema in posterior talus Inflammation of posterior recess of tibiotalar and subtalar joint Incomplete fracture with osteosclerosis