Hip dysplasia is a skeletal defect in dogs. In hip dysplasia, the ball portion (femoral head) of the hip is not securely seated in the socket portion (acetabulum). This condition is especially common in working and sporting breeds of dogs. Certain breeds are definitely predisposed . (see chart from the Orthopedic Foundation for Animals further down this page)
Hip dysplasia is an inherited problem which is not usually present at birth. It develops within the first 6-8 months of life. The exact cause is unknown, but it is generally accepted that the condition is from the combined action of an unknown number of genes. Nutrition and environment are also believed to be contributing factors.
Concerned dog breeders and veterinarians have tried to reduce the incidence of hip dysplasia through selective breeding. X-rays has been performed on potential breeding pairs in an effort to determine the status of the hip joints. Some progress has been made toward reducing the severity and incidence of canine hip dysplasia, but progress has been slow.
Hip dysplasia is defined as a biomechanical disease. That is, the muscles do not develop and reach maturity at the same rate as the bones. Since the hip depends on muscle power to be stable, it can pull apart and trigger a series of events resulting in hip dysplasia.
If a pup is so poorly developed that it cannot walk, then the demands of the musculoskeletal support system are greater than the strength of the surrounding musculature. The muscles and ligaments are unable to maintain the needed relationship between the femoral head and the acetabulum. This results in a partial or incomplete dislocation of the femoral head. The acetabulum is unable to develop properly if the femoral head is dislocated, and is shallower than normal when the pup reaches maturity. When the femoral head is dislocated, its cartilage covering is subjected to wear and tear. This eventually leads to a miss-shaped femoral head , and osteoarthritis or degenerative joint disease.
The degree of hip dysplasia (mild, moderate, or severe) does not effect the signs exhibited by the affected dog. Signs may range from no symptoms to a pronounced disability. Symptoms can appear any time after 4 weeks of age, but are generally not detected, except in severe cases, until after 6 months of age.
Clinical signs of canine hip dysplasia include:
- Lameness after prolonged exercise
- A waddling or swaying gait
- Morning stiffness
- Difficulty in standing up
- Reluctance to move
- Change in temperament
- Pain when moving the hip joints.
These signs often appear worse on cold damp days.
Early clinical signs are caused by the stretching and tearing of the joint. This pain may disappear as scar tissue forms, and the puppy seems to get better. Unfortunately arthritis continues to get worse and eventually signs of pain appear again. Early treatment will slow or stop the development of arthritis.
The diagnosis of canine hip dysplasia is bases upon: history, symptoms, a complete physical exam, and X-rays. X-rays are necessary to confirm hip dysplasia. They can show:
- the shape and depth of the acetabulum
- the shape contour and position of the femoral head
- degenerative joint disease.
Hip dysplasia can be treated surgically, medically, or a combination of both. There is no cure for hip dysplasia, but with appropriate veterinary care affected dogs can live long, healthy, active lives. Non-surgical treatment can include:
- enforced cage rest when the dog is experiencing discomfort
- mild analgesics
- anti-inflammatory drugs.
There are several surgical procedures that can be attempted in young dogs, and if the disease is not severe:
- Cutting of the femur and/or the pelvis and repositioning the joint. This is recommended for dogs 6-12 months of age only.
- Cutting the pectineus muscle. This is useful in relieving pain in certain cases, but has no effect upon the progression of the disease.
- Removal of the femoral head and neck. and formation of a “false joint” between the proximal femur and the pelvic musculature. Small and medium sized dogs usually do better with this procedure than larger dogs.
- Total hip replacement. Although this procedure is expensive, many dogs are able to return to full activity .
HOW PREVALENT IS HIP DYSPLASIA
Any dog can have displasia. But, based on test results from the Orthopedic Foundation for Animals, the highest incidence of dysplasia is as follows:
12.Chesapeake Bay REtriever
17.Staffordshire Bull Terrier
23.Old English Sheepdog
25.Bernese Mountain Dog
28.American Pit Bull Terrier
30.Welsh Corgi Pembroke
31.Welsh Springer Spaniel
32.Black and Tan Coonhound
36.Greater Swill Mountain Dog
37.Welsh Corgi Cardigan
38.Bouvier Des Flandres
39.English Springer Spaniel
40.Irish Water Spaniel
42.Portugese Water dog
43.Curley Coated Retriever
45.Chinese Shar Pei
46.Australian Cattle Dog
62.Cavalier King Charles Spaniel
65.German Wirehaired Pointer
68.Nova Scotia Ducktolling Retriever
70.Kerry Blue Terrier
71.American Water Spaniel
72.American Eskimo dog
76.Wirehaired Pointing Griffon
77.Petit Basset Griffon Vendeen
87.English Cocker Spaniel
89.German Shorthaired Pointer
94.Flat coated Retriever
96.Soft Coated Wheaten Terrier
109.Main Coon Cat