Hip Dysplasia

As dog owners, we want nothing more than for our four-legged friends to romp freely and enjoy life. One potential and painful damper on that dream is hip dysplasia.

Canine hip dysplasia (CHD) is the most commonly inherited orthopaedic disease in dogs, affecting millions of dogs worldwide each year. CHD can affect any dog, regardless of breed, whether male or female, small or large.

CHD is a developmental disease, which means it’s not present at birth, but develops with age. Onset of canine hip dysplasia symptoms may be early, occurring when the dog is only about four months old; this early onset type of dysplasia is related to laxity or looseness in joints. Late onset hip dysplasia is frequently associated with osteoarthritis, an inflammation disease which causes joint cartilage to degenerate over time. By 2 years of age, 95 percent of dogs who have genes for hip dysplasia will begin to show evidence of the disease on x-rays.

 

What Is Hip Dysplasia?

Hip dysplasia is an inherited disease of the hip joint. The hip joint is a ball-and-socket joint, made up of a depression in the pelvis called the acetabulum (or “socket”), and the head of the femur, or thigh bone (the “ball”). In a normal hip joint, the head of the femur fits cleanly into the hip socket and is held in place by large muscles and a strong ligament that attaches the femur head directly to the acetabulum. In a hip joint that is dysplastic, either the femur head or the socket (or both) are abnormally shaped, and therefore don’t fit together correctly. This allows the femur head to slide out of place.

Over time, this constant sliding causes inflammation. The entire joint swells and its structure weakens. The nerve endings in the ligament and joint capsule also become stretched. This results in the development of osteoarthritis and severe, chronic pain.

It’s important to understand that hip dysplasia is not a congenital defect; it is not present at birth and if it does develop later in life, there are likely both genetic and environmental causes.

Although its development is primarily genetic, other factors can also bring about the onset of CHD, including rapid weight gain (especially in puppies), diet, pelvic injuries, weak hind limb muscles, excessive exercise, and repetitive strain injuries.

 

The Role of Genetics

Canine hip dysplasia is an inherited, polygenic disorder, which means that more than one gene influences the development of the disease. Because there are many different genes involved, and no one is sure exactly which genes are responsible for the development of CHD, the disease is not something that is easily removed from a particular breed.  Breeding only parents with healthy joints drastically reduces the chances of dysplasia in puppies.

 

Can Canine Hip Dysplasia Be Prevented?

Wise breeding decisions help reduce the incidence of hip and elbow dysplasia. Genetic testing is not yet available, but evaluating a dog’s joints with special x-ray techniques prior to mating is helpful. Quality breeders spend the time and money it takes to have their breeding dogs (both mum and dad) certified as being free of hip dysplasia. Screening and certifying dogs is currently done under the ANKC’s Canine Hip and Elbow Scheme, which uses an x-ray technique that requires general anaesthesia. Breeding only parents with healthy joints drastically reduces the chances of dysplasia in their puppies.

Besides screening for CHD in breeding dogs, there are other ways that the disease might be prevented. Studies have shown that slowing down a dog’s rate of growth in puppyhood can lessen the severity of hip dysplasia, and may even prevent it. Large-breed puppy foods are less calorie-dense and contain lower concentrations of calcium and fat in comparison to diets for other puppies. These characteristics help slow a puppy’s growth rate. Individuals fed this way still reach their optimum size; it just takes them a little longer to do so. Over-feeding, even if an owner is using a large-breed puppy formulation, reverses these benefits. Rapid weight gain will increase the likelihood of developing CHD because bones and muscles grow too quickly. 

Preventing hip dysplasia from developing, even if a dog is genetically predisposed to it, is often a matter of implementing healthy habits that are good for all dogs. Dogs that are overweight or obese are more inclined to develop the condition and suffer more pain and discomfort due to the extra pressure excess weight places on the joints. So keep your dog at a healthy weight. Giving a dog regular exercise, especially as a puppy, is also vital; but when a puppy, avoid high intensity exercise that involves jumping on hind legs and quick stops and turns that are necessary to catch or retrieve a ball mid-air. Repetitive motion activities that are unnatural to a dog’s movement should also be avoided. Instead, encourage gentle off lead play on soft surfaces such as grass and short walks.

 

What Are the Symptoms of Hip Dysplasia in Dogs?

Most dogs will begin displaying symptoms of hip dysplasia around one and a half years old. The skeletal condition can range from mild to crippling and may come in conjunction with osteoarthritis. Here are some of the signs you should be aware of:

 

  • Decreased activity
  • Decreased range of motion
  • Dislocation
  • Lame hindlegs
  • Loss of muscle mass in the thigh
  • Pain
  • Soreness
  • Stiffness
  • Trouble jumping or climbing stairs
  • Uneven shoulder muscles as a result of hind leg compensation
  • Unnaturally narrow stance
  • Unusual gait characterized by “bunny hopping”
  • Any puppy that is limping, reluctant to move, or having trouble standing up or walking needs to be evaluated by a veterinarian as soon as possible. They could have hip dysplasia or another serious condition.

 

How to Diagnosis Hip Dysplasia in Dogs

A vet can use many of the symptoms mentioned above to develop the diagnosis. However, the only way to confirm hip dysplasia is with an x-ray evaluation. On x-ray, a healthy hip joint shows a snug fit of the femur head against the acetabulum, with the acetabulum appearing to cover about three-fourths of the femur head. In dysplastic dogs, the femur head appears to jut away from the acetabulum, and more space is visible between the two bones. Displacement of the head of the femur is considered the hallmark of CHD.

If your dog has been diagnosed with hip dysplasia, your veterinarian will speak with you about the pros and cons of treatment options.  Then you can make an informed decision about which procedure is best for you and your pet.

 

Treatment for Hip Dysplasia in Dogs

Canine hip dysplasia treatment typically involves a multi-plan attack. The majority of dogs can be helped without such a drastic intervention as surgery. Many factors go into how necessary a hip dysplasia surgery is: age, cost, degree of osteoarthritis, intended function (for example as a service dog), severity of joint looseness, size, and your veterinarian’s recommendations all factor into this kind of decision. Nonsurgical management typically involves life-style changes including exercise adjustments,exercise such as swimming which carefully moves and exercises the joint passively can help maintain the integrity of the muscle and decrease stiffness in the ball-and-socket joint, Weight control is critical to ensuring your dog’s joints are not overburdened with excess weight, pain management and drug treatment. The decision on what treatment would best suit your dog should be discussed with your vet.

Surgery is frequently used to improve the discomfort of osteoarthritis resulting from HD, yet it remains unclear whether one surgical procedure is likely to result in a better outcome and should be recommended over another. Surgical intervention should be discussed thoroughly with your vet. To date the literature fails to provide an abundance of evidence to demonstrate that any surgical procedure will consistently allow a return to normal function for dogs with HD. Surgical options include juvenile pubic symphysiodesis, triple pelvic osteotomy, femoral head and neck ostectomy and total hip replacement.

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