Posterior ankle impingement syndrome

Posterior ankle impingement (PAI) syndrome is one of the impingement syndromes involving the ankle. It is classically described in ballet dancers.

It is usually a unilateral phenomenon. Bilateral posterior ankle impingement syndrome has been described but is rare 5.

Patients usually present with sharp pain at the back of the ankle upon plantar flexion. The pain might persist for some time after such a movement. 

Thought to occur from repetitive ankle plantar flexion.

  • Stieda process
  • os trigonum
  • fracture involving lateral tubercle of posterior process of talus
  • prominent superior surface of calcaneal tuberosity
  • prominent downslope of posterior tibial articular surface
  • any abnormal calcification/ossification posterior to the ankle
  • may demonstrate posterolateral capsular thickening and synovitis involving an intact posterior talofibular ligament (PTFL)
  • there may be tenosynovitis involving the flexor hallucis longus (FHL)
  • may show one or more of the predisposing anatomical factors
  • accompanying bone contusion may be present, involving the lateral tubercle of the posterior talar process
  • T1: low signal in areas of bone bruising
  • T2/STIR: high signal posterior to ankle in areas of bone bruising
  • PD/PD fat saturated: high signal posterior to the ankle
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Article information

rID: 10754
Synonyms or Alternate Spellings:
  • Talar compression syndrome
  • Os trigonum syndrome
  • PAI syndrome
  • Posterior ankle impingement (PAI) syndrome

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Cases and figures

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