Posterior ankle impingement syndrome: MR imaging findings in seven patients.

PURPOSE: To report the magnetic resonance (MR) imaging findings in seven patients with posterior ankle impingement (PAI) syndrome.
MATERIALS AND METHODS: Seven patients-three ballet dancers, one badminton player, one soccer player, one hockey player, and one construction worker-who presented with posterior ankle pain were assessed with MR imaging. Their clinical records and imaging studies were reviewed. The MR imaging studies were assessed for the presence of abnormal bone marrow signal intensity, osseous lesions, and soft-tissue abnormalities.
RESULTS: One patient was treated surgically. In all patients, MR imaging demonstrated abnormal bone marrow signal intensity in the os trigonum and/or lateral talar tubercle, consistent with bone contusions. Two patients had a fragmented os trigonum or lateral tubercle, and two had a pseudoarthrosis of the posterolateral talus. Increased signal intensity was seen with distention of the posterior recess of the tibiotalar joint in two patients and with distention of the posterior recess of the subtalar joint in four patients. Three patients had fluid accumulation in the flexor hallucis longus tendon sheath.
CONCLUSION: Bone contusions of the lateral talar tubercle and os trigonum are prevalent MR imaging findings of PAI syndrome. MR imaging clearly depicts the osseous and soft-tissue abnormalities associated with PAI syndrome and is useful in the assessment of this condition.