Osteochondritis Dessicans OCD is a juvenile bone disease that can affect the shoulder, stifle, tarsal and elbow joints of young dogs. Osteochondritis Dessicans is a subset of osteochondrosis.
Osteochondrosis is a failure endochondral ossification. A region of cartilage which was destined to turn to bone, does not. Thus, a focus of overly thick cartilage (fig. 1) remains (versus the surrounding joint surface cartilage). The deepest layer of this thickened cartilage is inadequately nourished from joint fluid (squishing into cartilage with weight bearing), dies, and detaches from the underlying bone. Eventually this fissure propagates to the joint surface and a “flap” (fig. 3) develops (dessicans). Cartilage debris and inflammatory mediators are released into the joint fluid and inflammation ensues. With time, arthritis/degenerative joint disease occurs.
Elbow OCD affects young large and giant breed dogs. Limping is the common clinical sign. Many dogs have pain on elbow flexion and extension, as well as limited range of motion. Radiographs (fig. 4) are helpful in diagnosing OCD but arthroscopy is used for definitive diagnosis.
Treatment for elbow OCD involves arthroscopic debridement followed by a cartilage grafting procedure called osteochondral autograph transfer system (OATS). Some forms of biological treatment such as platelet rich plasma or stem cells have also been advocated but will not result in cartilage regeneration despite claims made by some.
OATS involves harvesting an osteochondral plug (fig. 5) from the periphery of one joint (in canine patients the plug is usually harvested from the stifle joint) and transferring the plug to fill the OCD lesion (fig. 6).
Synthetic plugs are also being investigated for the treatment of canine OCD and are currently being used in clinical trials.
Prognosis for elbow OCD treated using arthroscopic debridement followed by OATS procedure is good to excellent depending on the chronicity of the problem, existing osteoarthritis and size of the lesion.