Degenerative joint disease with osteochondrosis of the proximal interphalangeal joint in young horses.

Degenerative joint disease of the proximal interphalangeal joint was diagnosed in 9 joint of 6 horses. All of the horses were 3 years old or younger and the affected joints were in the hindlimbs. Radiographic evidence of osteochondrosis involving the distal end of the proximal phalanx was apparent in 5 joints. Lameness and local soft tissue swelling were prominent in all cases. In 1 horse euthanatized tissues because of lameness, histologic examination of joint tissues revealed osteochondrosis as well as severe osteoarthritis. Surgical arthrodesis of the affected joint was performed on 2 horses, one of which became sound.