Hip Dysplasia

Definition: Dysplasia means the abnormal development of a tissue or organ.

Hip dysplasia is abnormal development of the hip joint which results in an ill-fitting hip joint resulting in looseness and instability. The unstable joint undergoes partial dislocation when the animal is normally weight bearing. This causes stretching and damage to the ligaments and soft tissues around the joint and abnormal wear and tear of the cartilage in the joint. Tiny stress fractures can occur in the bone beneath the cartilage layer. This results in pain, inflammation and progressive irreversible arthritis of the joint. Both hips are usually affected.

Severely affected dogs usually start showing signs of pain between 4 and 10 months of age such as stiffness after rest, difficulty rising and a reluctance to exercise. Sometimes a clunk can be heard when the animal gets up or walks. They often have an exaggerated swaying movement of the hind quarters when walking.

Manipulation of the hips will reveal pain and instabilty. Xrays will confirm the diagnosis and also help to assess the severity of the problem.

What can be done to help?

Unfortunately there is no way to make these hip joints normal.  Most affected dogs will need some anti-inflammatory treatment from time to time to keep discomfort under control; strict weight control and limited regular exercise are very important to limit problems. Supportive treatments such as Cartrophen injections (administered by your vet) and a glucosamine/chondroitin supplement can be beneficial.

Happily, about 60% of affected dogs treated conservatively will have a normal adult lifestyle with little or no need for ongoing medication, as the pain associated with HD (hip dysplasia) can subside by the time the dog is about 2 years old. However, there still may be further problems with advancing arthritis later in life which may require further treatment.

If the level of discomfort is not adequately controlled with these measures, then surgical intervention may be considered. These are fairly radical procedures which involve resetting the pelvis to allow the hips to sit better in the joints; this is specialist territory and can be very expensive.

In older dogs, total hip replacement has become an option in recent years and seems to have a good success rate when performed by a specialist surgeon. Sometimes, a salvage procedure (called an excision arthroplasty) may be indicated, where the head of the hip is removed; this can be very successful in smaller breed dogs. Larger heavier breeds do better with hip replacement.

The success rate for total hip replacement or excision arthroplasty is NOT affected by the severity of the arthritis that is present, which means that there is no need for a hasty decision. Where severe dysplasia/pain is diagnosed before significant damage has ocurred, careful consideration should be given to  the risks/benefits of early surgery (eg. triple pelvic osteotomy (TPO)).