Subchondral bone sequestrum formation in the proximal intra-articular and osteochondral region of the third metatarsal bone of an Appaloosa mare treated for septic arthritis.

The present report highlights the importance of arthroscopic lavage to visualize the cartilage surface and the benefits of advanced imaging to detect associated changes within the bone earlier than conventional radiographs. To our knowledge, no reports exist of intra-articular subchondral bone sequestra in the tarsometatarsal joint in horses.