History: 8-year-old Quarter Horse mare presented for advanced imaging of the tarsus/proximal metatarsus. The mare had a history of a RH lameness that responds to intra-articular therapy of the distal tarsal joints, but only for a short period of time.

Diagnosis: Marked osteoarthritis and partial ankylosis of the distal intertarsal joint. Recommended surgical ankylosis due to progression of disease and lack of response to therapy.