What is hip dysplasia?
The hip joint attaches the hind limb to the body. This joint is a ball and socket that is held together by muscles, joint capsule and a ligament. The inside of the joint is covered with glistening cartilage that allows the joint to move smoothly. The joint fits tightly and remains in the socket during rest and play.
Hip dysplasia is a condition in puppies that begins with looseness of the supporting muscles, ligament and joint capsule of the hip. As the ball separates from the socket, the joint gradually becomes deformed and no longer fits well together. With time, arthritis of the hip develops. Although defective genes cause hip dysplasia, limited food consumption frequently will slow the growth of affected puppies and prevent the development of this condition.
Dogs are commonly five to eight months of age when signs first appear. Any breed can develop this condition; however, large breeds are most commonly affected. Some dogs, however, are quite geriatric when the problem is found. Warning signs of hip dysplasia may include an awkward gait that is frequently dismissed as “a clumsy puppy.” Waddling of the hind quarters when walking; bunny hopping; stiffness when first getting up from a nap; a clicking sound heard from the hind end; lameness on one or both hind limbs; shortened stride of the hind limbs; exercise intolerance; and pain upon petting the hip region are clinical signs that also can be seen by pet owners. Signs that your veterinarian may pick up include pain on extending or spreading the hips apart. Your veterinarian may also detect looseness of the hips called the Ortolani sign. In some cases this abnormality can only be detected when your dog is sedated.
The diagnosis of hip dysplasia is based on the evaluation of X-ray images of the pelvis. In order to obtain properly positioned X-ray images, your dog may need to be sedated. Only looseness of the hip joints may be seen on the X-ray image in young dogs. As the dog matures, the affected joints develop bone spurs, a sign that the hips are degenerating.
Nonsurgical treatment of hip dysplasia includes exercise restriction and administration of medications to relieve pain.
Triple pelvic osteotomy (TPO)
For dogs between the age of 5 and 12 months, a triple pelvic osteotomy is ideal if there is minimal to no arthritis. Hip dysplasia must be detected early in the course of the disease before significant joint damage occurs for the TPO to be effective.
The TPO is performed to relieve pain, restore function, and stabilize the hip joint so it will develop more normally. Studies in humans and in dogs show that early correction of abnormal weight-bearing forces across the joint in a patient afflicted by hip dysplasia results in a more “normal” joint. The objective of the TPO procedure is to stabilize the hip joint and prevent the progression of debilitating arthritis.
During the TPO procedure, three cuts are made in the pelvis, and the hip socket is rotated over the head of the femur bone. A specialized plate and screws are used to secure the pelvis in place. During the healing process, the femoral head becomes seated deeply within the hip socket. As a result, the femoral head no longer pops in and out of the joint when your companion runs and plays.
Total hip replacement (THR)
Total hip replacement is used in medium to large patients that are no longer candidates for TPO. During the procedure a metal and plastic cup are placed in the hip socket and a metal implant is placed in the femur bone.
Femoral head and neck ostectomy (FHO)
Femoral head and neck ostectomy involves removal of the head and neck of the femur bone. Scar tissue develops to form a false joint.
In general, about 90% of acceptable candidates that undergo the TPO surgery achieve full limb function and return to athletic activities. Similarly, total hip replacement has a 90 to 95% success rate. The FHO has the best outcome in small dogs, yet intermittent hip soreness may be seen with heavy activity.
For more information on this subject, speak to the veterinarian who is treating your pet.