Hip dysplasia is a common condition of large breed dogs. Many dog owners have heard of it, but anyone owning a large breed dog or considering a large breed dog should be become familiar with this condition. The larger the dog, the more likely the development of this problem becomes, particularly as the dog ages.
What is Hip Dysplasia?
The term hip dysplasia means abnormal growth or development of the hips. Hip dysplasia occurs during a puppy’s growing phase and affects the ball (femoral head) and socket (acetabulum) joint. Within the joint, lubricating fluid coats the smooth cartilage surfaces so there is no friction within the joint. In dogs with hip dysplasia, this joint does not fit together smoothly. The socket tends to be flattened and the ball sits looser within the socket allowing it to slip around. This makes for a very unstable joint and leads to significant arthritic changes.
What age dogs are affected?
There are two sets of patients typically affected by hip dysplasia. The first group is the adolescent dog, typically 6 to 18 months of age. These dogs have hip dysplasia but have not yet developed arthritis. These dogs may be lame in a back leg, have pain on extension of the hip joint or be seen to “bunny-hop” with their back legs.
If the hip dysplasia is not picked up at an early age (which is particularly common in milder cases) these dogs will often present as elderly patients when the arthritis is severe enough to cause pain and discomfort. They will often be lame, stiff and have pain and a reduction in motion when evaluating their hips.
The degree of arthritis and changes seen on x-ray of these dogs does not necessarily correlate to their pain levels so treatment is based more so on symptoms presented.
What causes Hip Dysplasia?
The primary cause of hip dysplasia is genetic and certain breeds of dog are more likely to have hip dysplasia such as Labradors or Standard Poodles. However just because a puppy’s parents have normal hips does not mean they will, as the condition has been known to skip generations. For this reason most responsible breeders provide prospective owners with hip scores (a scoring system devised by radiologists and veterinarians) of previous generations to ensure the likelihood of hip dysplasia is as low as possible.
Nutritional factors are also important in the development of hip dysplasia. Studies have indicated large breed puppies that are fed too much protein, calcium or in general are overfed and much more likely to develop hip dysplasia as their bones and muscles grow at differing rates. For this reason, it is recommenced that large breed puppies be fed large-breed specific foods that take into account these specific requirements.
The first step is examination by a veterinarian. Full extension on the dog’s hind legs may cause pain. Walking your dog around may demonstrate a hip swivel or “bunny-hop” motion. An ortolani test is also used which is when the leg is opened out away from the body whilst palpating the hip joint. Dogs with hip dysplasia will have a distinctive “pop” indicating the ball has come out of the socket joint. Many dogs will not tolerate this test conscious.
If hip dysplasia is suspected x-rays are used to confirm diagnosis. These must be performed under general anaesthetic to ensure the patient is still and can be carefully positioned to ensure diagnosis is achieved. The Ortolani test is often performed whilst they are under anaesthetic to further confirm hip displacement.
Australia’s hip scoring is based on a UK system that allows breeders to get their dog’s x-rayed as a screening process for hip dysplasia. These x-rays are examined by veterinary radiologists and a score is given based on a number of variables. Generally, breeding is only recommended if the dog’s hip score is lower than the breed’s average. Responsible breeders should be able to provide you with hip scores of the puppy’s parents and potentially grandparents for consideration.
Some breeders or owners also use PennHip certification which is a similar screening program that originated in the U.S.A. Puppies can be certified as young as 16 weeks of age with this system.
Is surgery the best treatment for Hip Dysplasia?
The first step in establishing whether surgery is right for your pet is referral to a veterinary orthopaedic surgeon to discuss your options. Whereby this is not a financially viable option for you, your vet may be able to perform salvage procedures if the hips are causing significant pain or discomfort. Most surgical options are expensive and involve a significant recovery period so should not be entered into lightly.
Triple Pelvic Osteotomy
This surgery is appropriate for young (age 8-18 months) dogs with dysplasia but without degenerative arthritis changes. This means that there is a window of opportunity for this surgery and if the dog develops arthritis or becomes too old, it will be too late for this surgery to be performed. In this surgery the acetabulum is essentially cut free of the rest of the pelvis, re-positioned for a tighter fit on the femoral head, and then plated back into place.
Many times, surgery on one hip leads to positive changes in the other hip so that surgery on the second hip is not necessary. Alternatively, it is possible to do the TPO on both hips if it seems clear that ultimately both will need surgical correction. This surgery requires a board-certified surgeon or a surgeon with extensive orthopedic experience. After care involves a good 3 to 4 months of exercise restriction. No leashed walks are allowed for 2 months except to go outside for elimination. Generally total hip replacement is strongly preferred over this surgery.
Femoral Head/Neck Ostectomy
This surgery is commonly referred to as the FHO and is best used for smaller dogs or very active dogs. The femoral head is cut off and removed, allowing the joint to heal as a false joint (just a capsule connecting the two bones but no actual bone to bone contact). If the dog is not carrying too much weight, a false joint is strong enough. If the dog is very active, a false joint will form quickly. The pet typically does not want to use the leg for the first 2 weeks but should at least be partially using the leg after 4 to 6 weeks. The leg should be used nearly normally after a couple of months. Many veterinarians are well experienced with this surgery and often a specialist is not needed. This surgery is typically substantially less expensive than the other procedures.
Total Hip Replacement
This procedure is for dogs with significant pain or established degenerative hip changes. The hip is completely replaced with a prosthetic hip. This procedure may sound radical, but it has been commonly performed for nearly 20 years in dogs with great success. This is a highly invasive procedure, obviously, and infection must be avoided at all costs (no skin disease can be present in the skin over the hips, extra precautions for sterility are used). Despite this the rate of complications is very low if performed by a skilled specialist surgeon. Expect about 3 months of exercise restriction after this procedure. Usually only one hip receives surgery at a time. Often only one replacement is needed, and the pet does well enough not to need surgery on the other side.
“DAR” stands for dorsal acetabular rim. In this procedure, bone grafts taken from other areas of the pelvis are used to build a longer rim on the acetabulum so that the femoral head will have a deeper socket in which to fit. This procedure is best done in dogs that are too old for triple pelvic osteotomy or have just started developing degenerative arthritis. This is a new procedure in the hip dysplasia arena and is not commonly performed in Australia. Long-term success (i.e., how patients do when they are old) is not really known as the procedure has not been performed long enough to collect results from many patients. A specialist is needed for this surgery.
Juvenile Pubic Symphysiodesis
This surgery is performed on young puppies before age 5 months, so it is generally done as a preventive procedure or if pain on hip extension is recognized at a very young age. The pubic symphysis is the cartilage connecting the right side of the pelvis to the left side. As an individual matures, this cartilage converts to bone and the two halves of the pelvis fuse permanently. This surgery prematurely seals the symphysis, which in turn results in rotation of the developing hip sockets into a more normal alignment. While studies show promise, because this procedure is done on puppies who do not yet actually have hip dysplasia, it is hard to evaluate success. In high risk breeds many vets recommend this reasonably low-invasive surgery as a preventative measure.
What Non-Surgical Treatment is Available?
Non-surgical treatment of hip dysplasia is essentially the same as non-surgical treatment for any other type of arthritis. There are nutritional supplements to help repair cartilage, pain medications, and anti-inflammatory medications. Physical therapy and massage are also important and helpful in non-surgical joint therapy. For any patient considering medical management of hip dysplasia, an arthritis management plan should be devised and will be life-long.