Hip dysplasia

Hip dysplasia is the abnormal development (dysplasia) of the coxofemoral (hip) joint that can affect both hips.

The condition occurs when the laxity present in the hip leads to an instability. Abnormal forces act on the joint which stretch the fibers of the joint capsule (fibrous envelope surrounding the joint) and the ligament of the femoral head (ligament that attaches the femoral head to the bottom of the acetabulum).

The movements of the bone of the joint being more limited in the space causes repeated coxofemoral subluxations and the rubbing of the structures against each other with the appearance of micro- fractures around the edge of the acetabulum as well as damage to the joint cartilage which translates into pain and limping of variable intensity.

The presence of joint damage and chronic inflammation cause changes in the bones at the level of the joint surface with the progressive installation of osteoarthritis that will persist for the entire life of the dog.

In a very young animal, it is sometimes possible to detect discomfort or pain as well as joint instability by placing the hands on his hips while he walks. If there is a subluxation of the hip, a « pop » may sometimes be felt when the member stands up on the ground.

The radiographic examination of the animals’ hips under general anesthesia, using the « 𝑃𝑒𝑛𝐻𝑖𝑝 » method, may be done as early as at sixteen weeks of age.

This method evaluates the integrity of the conformation of the hips by using three different views. They permit not only the detection of the presence of arthritic changes if any but they also verify if the hips are loose and, if so, to calculate precisely the degree of laxity present. This information is important, since the higher the degree of laxity, the greater the risk of subluxation and the eventual appearance of osteoarthritis is elevated.

While the animal is under anesthesia, we can also take the opportunity to perform specific manipulations on his hips in order to evaluate the degree of laxity.

Several symptoms may be an indication of pain in a dog suffering from hip dysplasia:

•  Decrease in the tolerance of exercise.
•  Reluctance to walking, running, jumping and climbing the stairs. Certain dogs in a lot of pain may even show a reluctance to getting up.
•  Limping from one or both of the back paws. A rolling gait is classically observed (rolling of the hips).
•  Bunny hop like running (simultaneous propulsion of the back paws).
•  Loss of muscle mass in the thighs.

Many dogs show no obvious symptoms of pain.

Others, on the other hand, may demonstrate pain at around 6 to 8 months of age. This may then diminish with growth and then reappear several months to several years later when the osteoarthritis sets in. At this time, the animal may limp following intense exercise or even manifest stiffness after a prolonged rest.

An excess of weight may exacerbate the symptoms.

Several treatment options are available. They depend upon several factors:

•  The age of the dog;
•  His degree of discomfort;
•  Orthopedic exam and x-rays;
•  The wait time and the budget of the client.

The condition can be medicaly or surgically treated.

Medical treatment is essentially aimed at limiting the progression of the osteoarthritis. This is how it’s done:

Firstly, if the animals’ weight is optimal, it is very important that it remain that way. To ensure this, his level of activity as well as the amount of food that he ingests must be controlled.

It is very important that the number of calories ingested do not exceed the number of calories spent. This way, when calculating the amount of food to give, not only his weight but also his build and his lifestyle must be taken into account.

We must not forget to take into account the number of calories provided by the treats that he eats, because these can make the difference between a healthy weight and an excess of weight. A food specifically conceived to optimize joint health should be privileged and the quantities calculated in function with the specific caloric needs of the animal.

If, however, the animal is overweight, it is imperative that he lose weight. A weight loss diet will therefore be indicated. Only a limited number of foods approved both for weight loss and the maintenance of healthy joints presently exist on the market.

Next, supplements and chondroprotectors are required to protect the joint cartilage.

Finally, anti-inflammatories may be used as needed.

Even though about 75% of young dogs affected by hip dysplasia who are medically treated can live an almost normal life but non sportive once their growth is finished, the other 25% of dogs require surgical treatment.

Unfortunately, since dysplasia is significantly damaging to the quality of life of the dogs affected, many finish in euthanasia.

In order to avoid this from happening, it is recommended that dogs for which the condition has been detected early, that is to say before the appearance of osteoarthritis, be operated quickly allowing them the opportunity to live an active life without osteoarthritis or pain.

Juvenile pubic symphysiodesis:

It consists of a technique that, when performed during the growth of the dog, stops the growth of the portion before the pubis, which causes, in the months following the surgery, a change in the position of the acetabulum and to a better covering of the femoral head.

Consequently, the laxity of the joint is diminished, reducing in this way the risk of subluxation.

To obtain the anticipated effect, the surgery must be performed before 18 weeks of age (22 weeks for giant breeds). It is a technique that is not costly and has few complications.

The prognosis depends on the age of the animal as well as the severity of the dysplasia at the time of the surgery.

Triple pelvic osteotomy:

As with the Juvenile pubic symphysiodesis, the triple pelvic osteotomy is a preventive surgery which consists of increasing the coverage of the femoral head by the acetabulum, preventing in this way the

coxofemoral subluxation and it should also be performed early in the life of the dog, that is before one year of age.

The prognosis is excellent for the return to an active life, including play and prolonged running, as long as the candidate was well chosen, that is to say before the osteoarthritis appears and while the hips are not too loose.

Among the most frequently observed complications associated with this surgery, there is the displacement/dislodging of screws, infections, the inability of the animal to adjoin his member to his body as well as the development of osteoarthritis despite the surgery.

In order to minimize the risk of such complications occurring, the animal should be kept at strict rest until the radiographs confirm bone recovery. Then, exercise can be reintroduced gradually. Surveillance and wound care are of equally great importance in order to prevent bacterial contamination.

As previously mentioned, aside from the genetic factor at the root of hip dysplasia, a rapid growth, a diet too rich as well as repeated trauma to the hip joints are all factors that can negatively influence the appearance of the disease in affected dogs.

There exists however precautions to be taken to attempt limiting or delaying the appearance and progression of osteoarthritis.

Firstly, it is primordial to control the weight of the animal so that he does not become overweight, which increases the stress on the joints.

To do this, it is recommended to give him a balanced diet for large breed puppies until one and a half years of age, and afterwards for large breed adult dogs being careful to calculate precisely the amount that he should eat.

We recommend that you ask one of our veterinarians or one of our animal health technicians to do the calculation rather than you relying on the quantities found on the back of the bags of food. In fact, they represent the average quantities without taking into account the individual build of the animal or his lifestyle.

Next, it is important to control the exercise that the animal does in order to avoid trauma to the hip joints.

Abrupt and high impact movements are to be avoided, such as prolonged running, jumping, abrupt starting and stopping, etc.

You must opt for a low impact exercise routine to be executed regularly. For example, swimming, walking in deep snow, calm walks, etc. We can however let an animal play who wants to while insuring to respect his limitations.

The administration of joint cartilage protectors (chondroprotectors) is also indicated, for the life of the animal.

Finally, anti-inflammatories and/or analgesics may be prescribed as needed.

Although a strong genetic component has been proven, a rapid growth and a diet that is too rich are factors that can influence the development of the disease. Repeated trauma may also worsen the problem by causing inflammation and joint effusion (liquid).

More often, this disease affects large bread dogs, especially those between 5 and 10 months of age whose hips are loose and those who are older and have arthritis.

Femoral arthroplasty:

This procedure, which consists of excising the femoral head and neck, is normally reserved for small and medium sized dogs who limp in a marked and repetitive manner.

It is performed when a preventative surgery can no longer be considered or that the complete prosthesis of the hip (refer to section on rescue surgeries) is not an option for the owner.

The prognosis varies greatly depending on the weight and muscular mass of the patient as well as on the diligence of the rehabilitation and the post-operatory physiotherapy.

In fact, the animal should have well developed muscles, because they will take over to stabilize the joint after surgery. An excess of weight however, would be harmful.

The functioning of the operated member of small and medium dogs is usually excellent whereas that of large dogs is good in 50% of cases.

Nevertheless the others continue to limp to variable degrees although generally less than before the surgery.

As for giant breed dogs, they should never undergo this intervention because they are far too heavy, which means that they don’t respond well.

Total hip replacement:

In order to completely eliminate pain and to permit the normal functioning of the hip, it may be completely replaced by an artificial prosthesis. The goal being to permit the animal to return to an active and sportive life.

It is the best option when a preventive surgery is not possible. This procedure gives an excellent joint function and can be performed at any time, as long as the growth of the animal is almost terminated.

Complications arise in about 10% of cases. The most frequent include dislocation, femoral fractures, the detaching of the implants and infections.

Keeping the animal at strict rest during 6 to 8 weeks after the surgery can minimize the risk of complications and maximize the recovery. Afterwards, activity can be gradually started again until the return to a sportive life is attained 3 months following surgery.