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A 22-year-old woman with a history of chronic right ankle pain for 8 years presented with pain exacerbation over the right talus over the previous 7 months. There was no recent history of trauma. The pain was aggravated by not wearing orthotics. No alleviating factors were identified. There was no history of instability or clicking. Past treatments included physiotherapy and ibuprofen.
Physical examination revealed pes planus with normal gait, normal weight bearing and normal range of motion. No skin changes or pain on palpation was identified. Focused neurovascular examination was normal. The anterior drawer, talar tilt and tibial torsion tests were all normal.
Ankle radiographs (figures 1 and 2) were obtained.
What is your diagnosis?
Talocalcaneal tarsal coalition.
Anteroposterior radiograph of right ankle
No abnormality is appreciable on this anteroposterior radiograph.
Lateral radiograph of right ankle
This image demonstrates a complete C-sign with osseous bridging. There is narrowing of the posterior subtalar facet, a short talar neck and a small dorsal subtalar beak.
Sagittal fast spin echo T1, sagittal fat saturated T2 and coronal fast short tau inversion recovery magnetic resonance images
The magnetic resonance images demonstrate bone marrow oedema across the middle subtalar joint, cortical irregularity and small subchondral cysts, in keeping with fibrous coalition.
Tarsal coalition is an abnormal union between two or more tarsal bones. The coalition can be osseous, fibrous or cartilaginous. Tarsal coalition is relatively common on autopsy, with an incidence of up to 1% of the population; although the majority of these are thought to be asymptomatic.1 Most cases of tarsal coalition …