Osteochrondrosis is a disruption of the cartilage development in large breed, rapidly growing dogs. As normal growth occurs the cartilage on the end of long bones (humerus, femur) must ossify/calcify or turn into bone. If calcification does not occur properly the cartilage becomes thickened and prevents joint fluid from reaching the other cartilage cells underneath. Without joint fluid these cells break down, causing cracks in the cartilage. This defective cartilage does not properly adhere to the mature bone that is already present, disrupting the normal gliding motion within the joint, causing pain, lameness and eventually arthritis. During movement these cracks can loosen, forming flaps that can break off and float freely within the joint, interfering with normal function. In some instances, the flaps can actually use the nutrients in the joint fluid and grow larger, becoming what are referred to as “joint mice.”
The joints most commonly affected by OCD are the shoulder, elbow, hock (ankle) and stifle (knee).
Lameness is commonly noted for the first time at 5 to 8 months of age. Diagnosis is based on physical exam and radiographs (x-rays). Radiographs show a flattened shadowed area on the bone that corresponds to the area of damaged cartilage. Medical management with NSAIDS (nonsteroidal anti-inflammatories) is generally unsuccessful and surgical intervention is usually required.
Surgery involves removal of the loose cartilage and curettage or scraping out the defective area, stimulating healthier tissue to fill the defect. Recovery time is generally short, usually about 6 weeks. Most patients start to feel better in about 2 weeks but leash restrictions are necessary for another month to allow for proper healing.