Several readers correctly identified the condition last week’s “Name that condition” photo, which came from Dr. Dee Griffin at the University of Nebraska’s Great Plains Veterinary Education Center. The necropsy photo, Dr. Griffin says, shows a case of Osteochondritis Dissecans (OCD).

Randall M. Spragg, DVM, was the first reader to send in a correct OCD diagnosis. Other correct answers came from Tami Radney, Phil Gill, Bob Glock, Harry Swanson and Serif Kose.

Other answers included arthritis of the lateral trochlea of the stifle, Patellar luxation and marble bone disease.

OCD, according to Wikipedia, is a joint disorder in which cracks form in the articular cartilage and the underlying subchondral bone. OCD usually causes pain and swelling of the affected joint which catches and locks during movement.

According to the Merck Veterinary Manual, the most common sites of OCD, which usually is seen in young animals, are the femoropatellar joint, tibiotarsal (tarsocrural) joint, fetlock (metacarpophalangeal and metatarsophalangeal) joints, and the shoulder. Animals with OCD of the shoulder usually present when less than one year old with severe forelimb lameness and possibly some muscular atrophy. Animals with OCD in the other joints usually present with synovial effusion and varying degrees of lameness. Diagnosis is confirmed with radiographs.