Osteochondritis dissecans

Shane Jackson M.A., Vet MB., MRCVS


Veterinary medicine is littered with technical terms and jargon which can easily cause utter confusion in the lay person.  Osteochondritis dissecans (OCD) is a good example and since we see quite a few dogs with this condition, I feel this is a good opportunity to explain about it.

Where two bones meet in a joint, the ends of those bones are covered by cartilage.  Osteochondrosis is the name given to a disturbance in the way in which cartilage forms as well as how the bones grow, since the two are linked quite closely.  Bone grows in two ways.  The shaft of the bone lengthens by new bone being made in a special site called the growth plate which is found towards the end of the bone.  As this is going on, the articular cartilage grows thicker and the inner layers also change to bone.  In cases of osteochondrosis, the articular cartilage thickens, but it does not get converted to bone.  Some of the cartilage then dies, probably because it outstrips its supply of nutrients.  Cracks appear in the cartilage and pieces of the cartilage can actually break off to float freely within the joint space.  There is usually quite a lot of inflammation of the joint when this happens.  In the strictest sense, osteochondrosis is termed OCD when there is inflammation and cracks or fissures.

From the above description, it can be seen that the condition is quite a painful one, and lameness results.  OCD affects the young dog or puppy, onset of signs being between four and twelve months.  Males are more commonly affected.  The condition is seen when dogs are growing fast and usually in males who grow more rapidly than females at this age.  Following on from this, it is usually seen in medium and bigger breeds of dog, though some breeds have a predisposition to be affected in certain joints.  For example, Labradors, Retrievers, Rottweilers often suffer elbow osteochondrosis, whereas shoulder OCD is commonly seen in Great Danes and Pyreneans.  Other joints which can be affected are the knee and ankle (stifle and hock), and, to a lesser extent, the hip and the spine.  When one joint is affected, the joint on the other leg is usually affected too, though signs may not appear at the same time in both legs.

OCD is diagnosed by X-raying the suspect joint(s) and once a positive diagnosis is made, most cases will require surgery to remove the offending piece of free floating cartilage, and to curette or smooth the roughened articular surface.  Following surgery, the patient should be confined to lead exercise for about four to six weeks, and the joint should be bandaged to give support.  Some cases of osteochondrosis may respond to conservative treatment comprising of rest and analgesia for several weeks.  It is generally felt that if conservative treatment does not help, or if the first signs are seen when the dog is older than eight months of age, the surgery is the only alternative.

Prevention of the condition is not always possible, but certain measures may reduce the impact of the problem.  In those breeds most likely to suffer from OCD, it is advisable to avoid excessive exercise in the young puppy.  Striking the right balance between what is too much is difficult, but excessive leaping and jumping can traumatise a joint and precipitate a problem.  Over feeding should also be avoided, particularly overfeeding