Hip Dysplasia: What You Need to Know About Surgical Options

oct. 23, 2012

Hip dysplasia is a developmental condition affecting both dogs and cats, but cats tend not to show signs due to their small, light and flexible body. According to Dr. Jim Turpel (a vet who has a special interest in orthopaedic surgery), he suggests you “select a dog from a breeder that has made a genuine effort to minimize the likelihood of hip dysplasia, and keep your puppy fit and lean”. He reminds purchasers of breeds prone to this condition to check that parents of the purchased pup are certified free of hip dysplasia—ask your breeder for written proof.

The abnormal hip joint wear and tear that results from the dysplasia leads to a flattened femoral head (top of the thigh bone that sits in the hip joint) that gradually slips out of a progressively more flattened joint socket. New bone may also develop in the joint area, causing arthritic pain—leading to lameness and reduced function.

Owners of dogs with hip dysplasia may relay to their veterinarian that their dog appears as if he is “slowing down”, by getting up and lying down more slowly, not jumping in or out of the car, is having trouble with stairs, may show evidence of muscle wasting around the affected upper hind limb(s), perhaps “bunny hop” when running or shuffle/waddle when walking. In advanced cases, afflicted dogs can be reluctant to move and show obvious pain and lameness when moving.

When it comes to how hips appear on X-rays (radiographs)—abnormalities in the films do not always correlate well with how severe the signs are. A dog with advanced changes on X-rays may not be showing expected degree of discomfort and a dog with minimal changes on X-ray may be quite sore. Sometimes young dogs may show signs of discomfort then gradually improve over the course of months, thus surgery is not recommended early in the course of the condition. According to Dr. Turpel “Despite having abnormal radiographs, a thorough examination of the entire back end must be performed to ensure that the pain is isolated to the hip joints since other conditions, especially torn cranial cruciate ligaments can mimic the signs associated with hip dysplasia”. He notes “If surgery is deemed necessary there are a few options available, however surgery is typically reserved for those cases that are unresponsive to weight management and medical therapy”.

The dog’s growth plates should be fully closed before being considered for surgery; most dogs undergoing total hip replacement are middle-aged or older. Before considering surgery, nutraceuticals such as glucosamine, or a course of analgesic or anti-inflammatory drugs may be prescribed. Body weight should be closely controlled, as heavy pets put a much greater strain on all of their joints.

Surgical treatment of the hip using THR (total hip replacement) to definitively repair this problem involves placing an artificial hip joint. Dr. Turpel suggests “Since its inception numerous improvements in both the implant materials and surgical technique now result in an 80 to 90% success rate for return to excellent pain free function of the leg(s)”. He goes on to say that the surgery involves the creation of an artificial ball and socket joint by removing the natural hip joint components (head of femur- “ball”, and acetabulum of pelvis- “socket”) and inserting synthetic replacement parts that result in a smooth, stable, pain-free hip joint(s). Unlike people, the lifespan of our pets is such that a one-time prosthesis should do, and repeat surgery to replace worn implants is not typical. A smooth gliding surface is left between the two implants.

After surgery, one can expect a pet to use the limb well in a week or two, but exercise restriction usually lasts for 2-3 months. Physiotherapy is typically recommended during recovery to assist return to mobility, and for maintenance of muscle strength and joint flexibility.

Complications of the surgery include infection, breakage of the femur where the prosthesis is inserted, dislocation, new bone growth, and loosening of implants. As well, the usual anesthetic risks are incurred. According to Dr. Turpel, “Despite the advancements in the THR surgery a 10% to 20% complication rate can still be expected”. And so, he says that despite the excellent outcome in the majority of cases, these complications in conjunction with cost of the procedure often times limit its application.

Other surgical options include:

Femoral head and neck ostectomy (FHO) or femoral head and neck excision/arthroplasty FHNE(A)

This operation is not a newer option, but is well suited for many smaller dogs and cats, and provides formation of a false new fibrous joint in the muscle tissues so there is no grinding together of the ball and socket. The procedure removes the head and neck of the femur. According to Dr. Turpel, “it typically results in a good return to pain free function of the limb(s), has a low complication rate, and is considered far more affordable”. But he also notes “the surgery has a much longer recovery period than THR (good weight bearing seem typically within 1 month and full recovery in 4 to 6 months) and FHO’s are frequently performed if serious complications with a THR are encountered”.

Triple Pelvic Osteotomy

This is a pre-emptive procedure in younger dogs, and was frequently performed prior to clinical arthritis, usually at 12-16 months of age, for dogs that had obvious changes in their X-rays. This surgery changes the biomechanic loading by realigning the bones of the pelvis in order to preserve the joint(s). According to Dr. Turpel,” it is still occasionally performed, however, it has largely fallen out of favour by many surgeons over the last twenty years as the necessity and success of the procedure has been questioned”.

If you pet is not as mobile as before, please contact your veterinarian for evaluation because successful management options are available.

(Thanks to Dr. Jim Turpel, of Upper Canada Animal Hospital, in Niagara-on-the-Lake for contributions to this article)