Canine Hip Dysplasia (CHD) is a very common cause of osteoarthritis in dogs.
Dysplasia means ‘abnormal growth or development.' When a puppy has hip dysplasia, the hips are structurally and functionally normal at birth, but develop abnormally due to a combination of genetic, hormonal and environmental factors.
Hip dysplasia is most prevalent in breeds that are stocky, round and heavy, but can occur in any breed. Breeds with a known genetic predilection include Bulldogs, German Shepherds, Golden Retrievers, Labrador Retrievers, Rottweilers, Dogue de Bordeaux, Mastiffs and Newfoundlands. Although genetics are important in the development of CHD, environmental factors are also at play. Non-genetic factors that have been proposed to increase the risk of CHD in our pets include rapid growth, excessive caloric intake during growth, and desexing prior to skeletal maturity.
The normal hip joint is a ‘ball and socket’ joint in which the ball fits tightly into the socket. The head of the femur is the ball, and then acetabulum of the pelvis is the socket. Dysplastic hips develop looseness or laxity of the connective tissues that hold the ball in the socket. In addition, the hip socket may develop to be too shallow and/or the head of the femur may develop to be misshapen, leading to incongruity (miss-match) and abnormal forces in the hip joint. Over time, this laxity and incongruity of the hip causes inflammation, excessive wear and tear, and ultimately painful osteoarthritis.
Signs of Hip Dysplasia
Clinical signs (or symptoms) may start as early as 5-8 months of age, depending on the degree of joint laxity and osteoarthritis. Early signs of lameness are related to microtraumas due to joint laxity, whereas clinical signs later in life are related to the onset of arthritis. Clinical signs may be subtle and may include decreased activity; reluctance to run, jump or climb stairs; lameness that is often worse after exercise; and difficulty in rising (especially in the morning).
Our options for treating CHD are greatly improved if laxity is detected earlier than 20 weeks old.
For this reason, your veterinarian will often try to palpate the hips for signs of laxity at your pup’s 10-12 weeks old vaccination health check. This Ortolani test will require your pup to lie on their back and be fairly still and relaxed during the manoeuvre, so understandably it will not be possible to do in all patients! We may recommend that your puppy has a short general anaesthetic or sedation to screen for hip dysplasia with physical manipulation and radiographs. This is particularly important if your puppy is an ‘at risk’ breed.
It is important to note that hip dysplasia is often diagnosed before you have even noticed any signs at all of limping in your puppy. Regardless of whether clinical signs have become apparent, early treatment of this condition is still recommended for the best long-term outcome.
The options available to treat hip dysplasia will depend on the age of your pet at the time of diagnosis:
Under 20 weeks old
If you pet is under 20 weeks old, the gold standard treatment is called a Juvenile Pubic Symphysiodesis (JPS). This is a minimally invasive procedure, which involves using cautery (using high temperature) to induce premature closure of the growth plates at the symphysis (or join) of the two halves of the pelvis. This encourages the hip socket to rotate as it develops, better ‘capturing’ the head of the femur as it does. JPS must be done by 20 weeks of age, with an ideal age of 12-16 weeks, in order to maximise the effects of the surgery.
Prior to arthritis
If your puppy is diagnosed after 20 weeks old, but before the onset of arthritis, our best option is a Double Pelvic Osteotomy (DPO). This procedure accomplishes the same ‘capturing’ of the femoral heads as JPS, but requires surgery to the pelvis. As such, your puppy will need major surgery, followed by 8 weeks of strict rest. If both halves of the pelvis are affected, two surgeries are performed 2-6 weeks apart.
After development of arthritis
If your pet already has radiographic evidence of wear and tear, we have the following options:
Conservative management: with a combination of weight loss, anti-inflammatories, supplements, arthritis injections, and physiotherapy/hydrotherapy/acupuncture
Total hip replacement surgery: if your dog has severe arthritic hip dysplasia we may recommend referral to a specialist for a total hip replacement
Femoral head and neck excision: if your dog has severe arthritic hip dysplasia and THR is too expensive, FHNE is a cheaper procedure that involves removing the head of the femur. This takes the joint out of the equation and relies on muscles to stabilise the limb. This means the leg will be pain free, but there may be some compromised function with this procedure.