Hip dysplasia is a deformity of the coxofemoral (hip) joint that occurs during the growth period. This hereditary condition creates a poorly fitting hip joint with increased laxity. As the dog walks, the laxity leads to abnormal wear of the cartilage surfaces and osteophyte (bone spur) development. Arthritis will eventually develop, causing pain in the joint. The degree of lameness that occurs is usually dependent upon the extent of arthritic changes in the hip joint.
Most breeds of dogs can be affected with hip dysplasia although it is predominantly seen in the larger breeds of dogs, such as the German Shepherd, St. Bernard, Labrador Retriever, Pointers, and Setters. There is equal distribution of the disease between male and female dogs.
The typical clinical signs of hip dysplasia are rear leg pain, incoordination, and a reluctance to rise. Wasting of the large muscle groups in the rear limbs may eventually develop. Most owners report that the dog has had difficulty in rising from a lying position for a period of weeks or months; lameness and pain subsequently develop. Again, the severity of signs and progression of the disease usually correlate with the extent of arthritis in the joint. Clinical signs can occur as early as 4-6 weeks of age, but most dogs manifest the disease as a lameness around one to two years of age. Dogs with mild hip dysplasia and minimal arthritis may not experience pain and lameness until they reach 6-10 years of age.
Diagnosis
Tentative diagnosis of hip dysplasia is made on the basis of history, breed, and clinical signs. A large breed dog that has been slow to rise for several months and now is lame is highly suspect for hip dysplasia; a dog which refuses to rise should also be considered a candidate. Because the clinical signs may mimic other diseases, final diagnosis of hip dysplasia can only be made on the basis of specific radiographic (x-ray) findings. To obtain the proper radiographs, dogs must be carefully positioned on the radiographic table. This procedure requires the use of a short-acting anesthetic. The radiographs are evaluated for abnormal shape of the hip joint and for degenerative changes (arthritis).
Treatment
The degree of clinical signs and arthritic changes in the joints determine the specific approach to therapy. Treatment of hip dysplasia may involve the use of drugs or surgery, or both. The options are as follows:
- Medical Management. A combination of medications, joint supplements, and lifestyle changes can often provide relief from pain. Non-steroidal anti-inflammatories (NSAIDS) are the most commonly used medications. Anti-inflammatory drugs should be combined with additional medical management strategies including weight management, physical therapy, and joint supplements. Please see our page on Osteoarthritis for additional information about medical management.
- Surgery: There are four main procedures: total hip replacement, femoral head ostectomy, juvenile pubic symphysiodesis, and pelvic osteotomy.
Total Hip joint replacement is possible, as is done in humans. Metallic ball and socket prosthetics are attached to the femur and pelvis in place of the abnormal ones. It is an expensive procedure, but it may give many years of pain-free use of the hips. Although the intent is for the implants to be permanent, complications may include infection or loosening after a period of time.
Femoral head ostectomy (FHO) is another choice. The hip joint is a ball and socket joint. FHO is the removal of the ball part of the joint. This gives excellent results in small dogs because a functional “false joint” forms. However, some large dogs may not form this “false joint” very well. This procedure is usually only used in large dogs if arthritis is very severe, if the hip dislocates, or if the expense of the other procedures is prohibitive. The FHO procedure is also known as a femoral head and neck excision (FHNE).
Juvenile Pubic Symphysiodesis is performed in juveniles (less than 5 months) with early evidence of hip laxity. The procedure involves application of an electrical current to a portion of the pelvic growth plate. By altering the pelvic growth pattern, an improvement in acetabular (the socket) coverage of the femoral head (the ball) is achieved.
Pelvic osteotomy is a procedure performed in juveniles (6-12 months old) in which the pelvis is cut in two to three places around the hip joint. The bone is rotated to create better alignment with the femoral head (the ball). It is reattached so that the joint functions in a more normal fashion without looseness and pain. This should only be performed in a young dog with no visible arthritic changes in the joint. It is an expensive procedure with a higher rate of complications.
I am considering breeding my dog. Can anything be done to prevent hip dysplasia in the puppies?
Research has shown that the cause of hip dysplasia is related to a combination of genetic and environmental factors. The disease is known to be an inherited condition, and the genetics of hip dysplasia are extremely complicated. In addition, environmental factors such as overfeeding and excessive exercise can predispose a dog (especially growing puppies) to developing hip dysplasia. Because the inheritance of the disease is so complicated, many questions remain regarding eradication of the disease.
Here are some practical suggestions:
- Have your dog radiographed before breeding to be sure the hips are normal. If they are not, this dog should not be bred.
- Consider a feeding program to slow growth. There is a growing body of evidence indicating that dogs that grow very rapidly are more likely to have hip dysplasia. Many authorities recommend feeding an adult-type food to puppies of high-risk breeds so their growth is slower. They will still reach their full genetic body size, but just not as rapidly. Some dog food manufacturers are now making puppy foods for large breed dogs. This is essentially the same approach as feeding an adult food because these puppy foods are formulated for slower growth.
- Avoid excessive exercise in a growing puppy. Any abnormality in the structure of the hip joint is magnified if excessive running and jumping occur. It is not necessary to treat your puppy as it were handicapped, but long sessions of running or chasing thrown objects can be detrimental to joints.
What does it mean to have the hips certified as normal?
The Orthopedic Foundation for Animals (O.F.A.) is an organization established for the purpose of standardizing the evaluation process of canine hip radiographs. The O.F.A. consists of a board of certified veterinary radiologists who are skilled in detecting hip dysplasia. If the radiographs submitted to the O.F.A. are declared normal, the dog is issued an O.F.A. certificate number indicating that it has normal hip confirmation. The O.F.A. requires that dogs must be a minimum of two years of age to be certified. Many breeders require that a dog must have an O.F.A. certificate before breeding is allowed.
Another hip evaluation program is called the PennHip method. Radiographs are made of the anesthetized dog in such a manner as to place outward force on the hip joints. This can reveal looseness in the joints that may elude detection by the more standard radiographic methods. It is also useful in identifying hip dysplasia in puppies as young as four months of age and has been shown to be a more objective measurement than O.F.A certification. Although any veterinarian can make the appropriate radiographs and submit them for O.F.A. certification, the PennHip method must be performed by a veterinarian specifically trained and certified in this procedure.