17-year-old female with pain in the subtalar joint, evaluate subtalar and ankle joint cysts There is enhancement of the synovium of the anterior and posterior recesses the subtalar joint. Although we see no enhancement of the synovium between the articular cartilage of the joint, there are multiple round foci of abnormal signal intensity and enhancement within the subchondral bone that may represent cysts or erosions, with edema and enhancement of the adjacent marrow. These cysts/erosions appear to communicate with the joint through small articular cartilage defects. Additional foci of subchondral edema and enhancement are noted more anteriorly, just lateral to the medial facet of the subtalar joint. We see no low signal intensity foci to suggest pigmented villonodular synovitis (PVNS) and we see no findings to suggest tarsal coalition.There are foci of susceptibility artifact traversing the medial malleolus obliquely, presumably reflecting prior surgery. This limits evaluation of the bone and cartilage along the medial aspect of the talar dome. There is minimal enhancement of the synovium of the anterior recess of the tibiotalar joint, which is of questionable significance. There are small subchondral foci of abnormal signal intensity within the posteromedial aspect of the talar dome with slight heterogeneity of the overlying articular cartilage, which are of uncertain etiology but may reflect degeneration or prior surgery.An os trigonum is noted with normal signal intensity. The remaining visualized bones appear normal. The talofibular, tibiotalar and calcaneofibular ligaments are intact. The deltoid ligament is intact. The Achilles, flexor, peroneal and extensor tendons are intact.
1.Subchondral cysts/erosions with adjacent marrow edema and synovial enhancement affecting the subtalar joint, suggesting an inflammatory arthritis. There are no specific findings of PVNS.2.Other findings as described above.