HIP DYSPLASIA – JPS, FHO, TPO, DPO, Hip Replacement

Canine Hip Dysplasia (CHD) can cause instability or a loose-fitting hip joint as they grow. Symptoms of hip pain, joint changes and limb dysfunction are caused by hip joint laxity. If the femoral head (the ball part of the ball and socket joint) is continuously moving abnormally, the acetabulum (socket) may become deformed. The outcome of joint laxity can be scar tissue development around the joint, a loss of cartilage which progresses over time, and osteophytes (bone spurs) which form around the ball and socket.

There are various causes of CHD. The biggest risk factor is hereditary (genetics). Complications with the development of CHD can arise if the pet experiences rapid weight gain along with growth due to an excessive intake of nutritional substance. Hip dysplasia is more commonly found in dogs of larger breeds.

CHD can be identified by the following symptoms: lameness/limping, unwillingness to jump or rise, shifting majority or their weight to their forelimbs, rear limbs showing a loss of muscle mass as well as hip pain.

There are two groups which dogs with CHD are divided into:

Group 1: Younger dogs that do not have arthritis, but have significant hip laxity.

Group 2: Older dogs that have hip arthritis due to CHD.

Firstly, your dog should go for an examination where gait changes evidence of hip laxity will be evaluated. It is essential that a thorough orthopaedic examination is done as the symptoms associated with CHD can also be caused by a number of other orthopaedic or neurological disorders. X-rays are an important part of diagnosing CHD. Sedation or anaesthesia may be required for relaxation and thus, a good X-ray. After two years of age, your dog can be certified by the Orthopaedic Foundation for animals which is an agency that does screening for caning hip dysplasia.

The susceptibility of specific breeds can be detected from the age of four months through stress radiographs. However, many dogs that show signs of CHD have another problem that causes their symptoms which is why it is so important for your dog to undergo proper examination.

There is no specific treatment that is best for CHD. The recommended treatment will depend on multiple factors which include: age, size, amount of pain and dysfunction, X-ray and examination results, your expectations and budget. However, it is not always necessary that a pet diagnosed with CHD receives treatment. Many younger dogs with CHD are able to function acceptably well into maturity without any crucial signs of hip pain. There are both medical and surgical options for dogs with CHD. The initial treatment for most dogs is usually medical management.

Medical treatment aims to improve your pets comfort without having to surgically intervene. This method includes: aggressive weight loss and management, consistent participation in low-impact activities such as walking or swimming, anti-inflammatory drugs that do not contain steroids, physical rehabilitation, supplements containing fish oil and osteoarthritis drugs. Dogs in group 1 may not have the same positive results from medical treatment as dogs in group 2. Thus, it may be necessary for early surgical intervention with juvenile pubic symphysiodesis or a proceduure (JPS) such as pelvic osteotomy.

JPS aims to alter the shape that the pelvis grows into by stopping the pubis (portion of the pelvis) from growing further as well as diminishing hip laxity through increasing the ball’s coverage by the socket. The surgical procedure is relatively minor and should be performed while the puppy is less than 18 weeks of age. However, symptoms of CHD are rarely visible at this age and thus examination and X-rays are needed.

Alternatively, an immature dog can undergo a double or triple pelvic osteotomy (DPO/TPO), regarded they are less than 10 months old and have CHD without arthritic changes. In these procedures, the pelvic bone will be cut in two (DPO) or three (TPO) places and the segments will be rotated in order for the ball to have more coverage by the socket, thus decreasing hip laxity. TPO is a common procedure that has been used for decades. With the recent improvement in technology of implant (locking plates and screws), only two cuts in the bone will allow for similar results.

If the immature dog has evidence of hip arthritis or an extreme case of hip laxity, TPO/DPO is not recommended. In order to determine if the dog will benefit from the procedures, it is important that they undergo examination and X-rays beforehand. If candidates are not fit for the procedure, they should be medically managed until they are able to have a total hip replacement (THR) or a femoral head ostectomy (FHO).

FHO can be a beneficial treatment for dogs who do not meet the criteria for specific treatments or are part of group 2. This process requires the femoral portion of the hip joint to be removed which reduces the pain caused by abnormal hip contact and the stretching of soft tissue caused by laxity. After FHO, there will be development of a “false joint”, which is the muscles around the hip putting pressure on the pelvis rather than the leg during limb movement. FHO is aimed more at relieving the pain associated with CHD rather than maintaining or recreating normal hip function. Thus, the FHO procedure is less desirable for larger dog breeds.

THR is an option for both group 1 and 2 dogs. This procedure both eliminates hip pain and mechanics similar to that of normal hip joint, it also allows for a more natural limb motion and function. The THR procedure is similar to that of humans as it involves replacing the ball and socket with metal and polyethylene substitutes. These components will be fixed in place with either “press fit” methods, bone cement or metal pegs.

TPO was previously performed on younger dogs with hip dysplasia to reorient the positioning of the acetabulum/socket over the femoral head/ball. This procedure proved to be quite successful, however, complications and discomfort post-operation were much higher compared to other procedures. Thus, it was modified into a double pelvic osteotomy. The difference with this procedure is that only two incisions are made and a bone plate is used to secure the osteotomy. The discomfort post-operation is minimized as a portion of the pelvis is left intact.

There are multiple factors to consider when deciding if a patient will benefit from DPO. It is important that patients fit the criteria for outcomes to always be good to excellent. The criteria is:

• A patient must be younger than 8 months of age
• Not be diagnosed with osteoarthritis
• A normal sized and shaped femoral head
• Femoral head falls into the right place of acetabulum without extra force or angulations

There is a very low risk of complications after DPO. However, if there is a complication, it will likely be minor in nature. JPS has a high success rate for elimination hip laxity. Aftercare tends to be fairly brief, mostly involving basic incision care as well as activity restriction for a short period of time.

Cases where complications arise after DPO and TPO are rare, however when they do, they could be screw loosening, limited limb range of motion and narrowing of the pelvic canal.

THR has a high percentage of improved limb function. The complications associated with this procedure include implants loosening over time, infection, femur fracture and nerve injury.

Following these procedures, the dog’s activity both indoors and outdoors should be limited until such time as they are deemed healed through examination or X-ray. This usually takes about six to eight weeks. It is usually necessary that your pet is under supervision after surgery to ensure they do not overuse the leg. Sometimes a sling can be used for assistance. Keep the dog away from slippery surfaces, stairs and other dogs. After the initial period of restriction, your dog’s activity can slowly be increased in order to get back to normal.

Recovery for FHO is slightly different. Results are dependent on the size of the dog and the quality of rehabilitation after surgery. Lameness is common with many dogs, however, functionality should show improvement compared to the preoperative state. Post FHO procedure, pets should use the limb in a controlled environment. The optimal outcome is only achieved through aggressive physical rehabilitation and supervised exercise. Improvement can take six weeks or more to become visible.