Chondritis dissecans of concave articular surfaces (acetabulum and glenoid fossa). Two case reports.

We report two patients who had chronic mechanical pain due to substantial cartilage defects documented by arthrography. One of these patients had pain in the hip and declined surgical treatment. The other had pain in the glenohumeral joint; surgery found a fissure in the glenoid fossa cartilage and provided prompt pain relief. These two cases serve as reminders that investigation of the cartilage and subchondral bone in young patients with mechanical pain should not be confined to the convex articular surfaces, although these are more likely to sustain trauma-related damage than concave surfaces. In both our patients, the diagnosis required thin-section computed arthrotomography.