Posteromedial ankle impingement is one of the impingement syndromes of the ankle. It usually follows an injury of the deltoid ligament 1-4.
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Epidemiology
It is one of the less common ankle impingement syndromes 2. It is associated with a previous ankle sprain and deltoid ligament injury 1-3.
Clinical presentation
Patients usually complain of pain at the posteromedial aspect of the ankle with passive and active movement, aggravated with plantar flexion and supination 2,3.
Pathology
Posteromedial ankle impingement usually occurs as a consequence of an acute traumatic injury. A typical injury mechanism is plantar flexion, inversion and internal rotation, which causes compression and injury of the posterior tibiotalar ligament and the posteromedial joint capsule 2. This typically leads to synovial thickening and synovitis, which then causes the symptoms and possibly further involvement of the adjacent flexor tendons e.g. the tibialis posterior tendon is involved in up to 40% of the cases 2,3.
Radiographic features
Typically demonstrates soft tissue thickening in the posteromedial gutter of the tibiotalar joint 1,2.
Ultrasound
Hypoechoic posterior tibiotalar ligament with loss of striped appearance and hyperemia on color Doppler 4.
MRI
Thickening and a loss of the striated appearance of the deep and superficial portions of the posterior tibiotalar ligament 3. Possible associated bone marrow edema in the medial malleolus and medial talus.
Typical signal characteristics of the posterior tibiotalar ligament:
T1: low signal intensity
T2/STIR: intermediate signal intensity
IW/PDFS: intermediate signal intensity
T1 C+ (Gd): avid enhancement
Treatment and prognosis
Initial treatment is usually conservative 2,3 but can also be surgical or performed arthroscopically 5,6.