Fig. 8

A 14-year-old girl with HA20 presented with pain in her ankles and feet. a Anteroposterior radiograph of the right foot demonstrates joint space narrowing of the talonavicular and calcaneocuboid joints (arrows). Similar but asymmetrical changes are present in the left foot (not shown). b Lateral radiograph of the right ankle demonstrates subtalar joint space narrowing with subchondral sclerosis and subarticular cystic changes of the inferior surface of the talus (arrow). c Coronal STIR of the right ankle demonstrates fluid tracking along the tibialis posterior tendon (arrow) with post gadolinium enhancement (not shown). d Sagittal STIR and e T1-weighted image with fat suppression and intravenous gadolinium administration of the right ankle demonstrate subtalar joint space narrowing and subchondral cystic changes with surrounding edema involving the inferior articular surface of the talus and contrast enhancement (empty white arrow). There is joint space narrowing and small effusion in the tibiotalar, subtalar, and talonavicular joints with synovial contrast enhancement. There is retrocalceneal bursistis (white arrow). Arthritis, tenosynovitis, and retrocalceneal bursistis are likely inflammatory with degenerative changes of the subtalar joint