Hip dysplasia

By Brandon Brooks, DVM
Copyright 1999, Brandon Brooks. Used with permission.

Hip dysplasia is the most common orthopedic disorder of the canine hip and is the most common cause of arthritis in the hip. It is an inheritable condition, and standards have been established by the Orthopedic Foundation of America and the Penn Hip Foundation to characterize dogs in terms of their hip status and breeding potential. Attempts should be made to breed this condition out of affected lines since it is such a debilitating problem and it can be corrected by appropriate breeding.

The hip joint is a ball-and-socket joint. The head of the femur, or the first long bone in the hind limb, forms the "ball" of the joint; the acetabulum of the hip bone, a cup-shaped structure, forms the "socket." Normally, these two structures interlock tightly with no "laxity" or abnormal motion. With hip dysplasia (dysplasia means misformed), there are varying degrees of laxity present in this joint, and over time as this dog walks, runs, plays, etc., the joint becomes more loose by the constant motion. With this abnormal hip joint motion, inflammation occurs, and this is when the animal begins feeling pain from the hip and will start to limp, have trouble getting up and down, and have difficulty negotiating stairs. As the abnormal motion continues, the process of arthritis begins to set in, wherein the joint fluid becomes filled with more inflammatory products and breaks down, leading to decreased nutrition of the joint cartilage. As the cartilage weakens, the bones begin to degenerate, all leading to continued progression of pain and clinical signs.

Medical therapies for this condition include anti-inflammatories such as aspirin or newer drugs made just for dogs, such as Rimadyl and Etogesic. "Nutraceuticals" like Cosequin have much promise, even though they haven't undergone extensive testing by the FDA at this point. Cosequin is chondroitan sulfate, a cartilage component, and it not only provides some measure of pain relief but it also attempts to reconstruct a healthy joint atmosphere by supplying the body with the building blocks for healthy cartilage and joint fluid. Much anecdotal success has been noted with this product, meaning it is known to work well but this isn't backed up by any firm research as yet. Adequan is an injectable product that has undergone evaluation by the FDA, and I've personally seen it work very well for many dogs, though it's not perfect. Animals get eight injections over four weeks, and Adequan also supplies joint fluid and cartilage components. Acupuncture is a promising alternative therapy that has also had some medical success.

Often hip dysplasia becomes a surgical problem, due to the fact that it inevitably progresses over time, and medical therapy can only go so far. Depending on how severe the degeneration is and the overall health status of the dog, different surgeries exist that can help solve the problem.

The ideal treatment is total hip replacement, wherein the defective ball-and-socket joint is replaced by artificial implants. This procedure was developed and perfected on the canine so that it could be performed in humans, so we owe them a debt of gratitude for this! This procedure is the best since it reconstructs the hip joint in the most effective way, but it is also the most expensive (about $2000 per hip) and is not for every dog.

Triple pelvic osteotomy involves breaking the hip in three strategic locations around the socket part of the joint (the acetabulum) and reconstructing it in such a way that it interlocks better with the loose ball part of the joint, the head of the femur. This can most reliably be done at a young age and is also very effective and also costly, though not so much as the total hip operation.

The third surgical procedure is a femoral head and neck ostectomy. This is a salvage procedure, meaning it does not reconstruct the hip joint but rather modifies it so as to eliminate the source of the problem -- namely, the loose "ball," or head of the femur. Any present arthritis and degeneration will still be present, so this means any signs such as limping or pain are likely to pervade, though these can often be managed successfully with medications mentioned above. Also, the progression of the arthritis is stopped or greatly slowed down by this procedure. This is the most cost-effective procedure (usually $400-600 per hip) and is chosen when the other procedures cannot be done either due to age, severity of arthritis, or cost.

Other surgical procedures exist that may offer some benefit, but this all depends on the surgeon's tastes. Sadly, many cases are put to sleep either due to the intense pain caused by arthritis or poor prognosis due to diagnosis of this condition at a very young age.