Canine hip dysplasia is a condition in which the ball and socket joint of the hip is malformed. This means that the ball portion and the socket do not properly meet one another. This results in a joint that rubs and grinds and does not slide smoothly.
Hip Dysplasia in Dogs
Hip joints are comprised of the ball and the socket. Hip dysplasia is caused by both genetic and environmental factors. Basically, hip dysplasia is a failure of the hip joints to develop normally. This malformation will gradually deteriorate the joint causing a loss of function.
This disease is one of the most common skeletal diseases seen in many animals, especially dogs. With this disease gender is apparently not a factor. However, some breeds of dog seem to have a genetic predisposition towards hip dysplasia. Often, the breeds most commonly affected are the large and giant breeds. These include the Great Dane, Saint Bernard, Labrador Retriever, and German Shepherd. Rarely is this disease seen in small dog breeds but they too can also be affected. In these breeds clinical signs of hip dysplasia may be hard to ascertain.
Hip dysplasia will usually begin to develop in a dog while it is still young. The first signs of this disease usually begin to show in dogs that are around four months of age. Cases of hip dysplasia that occur in older dogs are usually the result of osteoarthritis which is a form of joint inflammation (arthritis) that is characterized by a chronic deterioration of the joint cartilage.
Symptoms and Types
There are many different types of symptoms when it comes to hip dysplasia. These are all dependent on the degree to which there is laxity or looseness in the joint as well as the degree of inflammation in the joint. Even the duration of the disease plays a role in the symptoms and types of hip dysplasia.
For the most part, dogs suffering from this disease may show one or more of the following:
- Early disease: signs are related to joint looseness or laxity
- Later disease: signs are related to joint degeneration and osteoarthritis
- Decreased activity
- Difficulty rising
- Reluctance to run, jump, or climb stairs
- Intermittent or persistent hind-limb lameness, often worse after exercise
- “Bunny-hopping,” or swaying gait
- Narrow stance in the hind limbs (back legs unnaturally close together)
- Pain in hip joints
- Joint looseness or laxity – characteristic of early disease; may not be seen in long-term hip dysplasia due to arthritic changes in the hip joint
- Grating detected with joint movement
- Decreased range of motion in the hip joints
- Loss of muscle mass in thigh muscles
- Enlargement of shoulder muscles due to more weight being exerted on front legs as dog tries to avoid weight on its hips, leading to extra work for the shoulder muscles and subsequent enlargement of these muscles
Causes of Hip Dysplasia
This is one of the few diseases where both genetic and environmental factors play a role at the same time. These factors include:
- Genetic susceptibility for hip looseness or laxity
- Rapid weight gain and obesity
- Nutritional factors
- Pelvic-muscle mass
Diagnosis of Hip Dysplasia
The first step that your veterinarian will take is to give the animal a complete physical examination. He or she will do a complete blood chemical profile, as well as a complete blood count, an electrolyte analysis and a urinalysis. The inflammation of the joint is usually noted in the complete blood count.
A complete medical history of your dog in regards to parents and environment, the onset of the symptoms, and a list of possible incidents which may have contributed to the dog's symptoms. This is why it is always important to learn as much about the parents of a pup before acquiring the puppy. This type of information may determine if there is a genetic link involved.
Also, your veterinarian will also take x-rays to help visualize the signs of hip dysplasia. These x-rays will help to determine if there are any complications involved with the disease such as degenerative disease of the spinal cord, bilateral stifle disease, lumbar vertebral instability, as well as other bone-related diseases.
Treatment of Hip Dysplasia
Most dogs are treated for hip dysplasia as an outpatient and don't require surgery. Surgical candidacy will depend largely on the dog's size, age, and the intended function of the dog (does it have a working role or is it a companion dog). Treatment largely depends on the degree of osteoarthritis, the severity of the looseness of the joint, the preferred treatment of the veterinarian, and your financial ability to pay for the treatment. Physiotherapy is often prescribed to decrease the stiffness of the joint involved. Swimming is the usual form of physiotherapy recommended as it encourages both joint and muscle activity without any increase to the severity of the joint injury.
Weight control is a very important aspect in the treatment of hip dysplasia. Your veterinarian will usually recommend a strict diet so that the animal does not gain any weight which can severely irritate the inflammation in the joint.
In severe cases of hip dysplasia surgery may be the only option. These surgeries come in several varieties depending on the dog's age. TPO surgery is performed on dogs less than a year old. The purpose of this type of surgery is to rotate the socket of the dog. Juvenile pubic symphysiodesis surgery is done on dogs that are younger than six months and involves the fusing of part of the pelvis in an attempt to improve hip joint stability. Older more mature dogs may have a total hip replacement. But this type of surgery is usually done if the dog is not responding as expected to medical therapy or have severe osteoarthritis. Total hip replacement is usually very successful in most dogs but it is extremely expensive. However, hip replacement surgery is too expensive your veterinarian may perform an excision arthroplasty in which the ball of the hip joint is completely removed allowing the muscles to act as the hip joint. This type of surgery, though, only works on dogs that are less than 40 pounds that have really good hip musculature.
Your veterinarian will probably also prescribe anti-inflammatory medications to help reduce the swelling and inflammation. And for cases where severe pain is involved he may also prescribe pain medications.
Living With and Management of the Disease
Follow-up appointments are necessary so that the veterinarian can monitor any changes in the dog's hip dysplasia. There will also be a need for periodic x-rays that will be used to compare with previous x-rays. Dogs that have undergone surgery will require more x-rays so as to monitor the post-surgical healing process.
Dogs treated as an outpatient only will have x-rays taken to determine the rate of deterioration of the hip joint.
Dogs that are diagnosed with hip dysplasia should never be bred. This disease has a genetic component to it.