Hip Dysplasia

Hip dysplasia is a medical term that describes a malformation of the hip joint that leads to debilitating arthritis of the hip joint. The condition results from an inherited tendency for rapid bone growth without concurrent muscular growth to support the skeletal structure. The rapid bone growth results in laxity of the hip joint and deformation of the cup and ball portion of the joint. The laxity concentrates the weight bearing stress to a relatively small area of the cartilage. This leads to cartilage damage and development of arthritis. Various therapeutic options exist for hip dysplasia. Each treatment has advantages and disadvantages and is described below.

Triple Pelvic Osteotomy 
The triple pelvic osteotomy (TPO) is a surgical procedure that is designed to improve the stability of the hip joint and prevent development of arthritis. The surgical procedure involves cutting the pelvic bone in three different places to allow the acetabulum (cup) of the hip joint be rotated to cover the head portion of the joint. This creates a stable hip joint. Additionally, the weight-bearing stresses that were concentrated to a small area of the cartilage are distributed over a broader surface area, preventing further cartilage damage and arthritis. Very young dogs with hip dysplasia without arthritic changes are candidates for a TPO. Dogs are usually between 5 and 10 months of age when the surgery is performed, before arthritis has developed. Radiographs of the hip and, more recently, arthroscopic evaluation of the hip are used to determine if the dog is a good candidate for a TPO procedure. Usually the surgery is performed in both hips during separate surgical procedures approximately 4-6 weeks apart. Overall the TPO surgery is associated with a good outcome in dogs that are good candidates for the surgery: 80-90 % of dogs have a normal functional life without pain associated with arthritis of the hip. 

Total Hip Replacement Surgery 
The total hip replacement surgery is designed to eliminate the arthritic hip joint as a source of pain while replacing the ball and socket with a highly functional and durable prosthesis. The total hip replacement surgery is a "state-of-the-art" procedure very similar to the operation in people. The arthritic femoral head (ball portion of the joint) is removed and replaced with a metallic ball and stem. The arthritic acetabulum (cup portion of the joint) is removed and replaced with a high-density polyethylene plastic cup. The new ball and socket fit together to form a highly functional pain-free joint. Working dogs such as police dogs and search and rescue dogs can return to their duties following a total hip replacement surgery. More than 95% of dogs that undergo a total hip replacement surgery return to a normal level of function. Most dogs that have arthritis in both hips only require a hip replacement on one side. Careful screening prior to the total hip replacement is required to minimize the risk of complications and ensure a successful outcome.

Femoral Head Ostectomy (FHO)
The FHO is an older salvage procedure designed to eliminate the arthritic hip joint as a source of pain. The femoral head and neck is resected and a scar tissue cushion forms between the bones of the pelvis and femur. The scar tissue cushion and surrounding muscle support the weight that is normally transmitted through the hip joint. Small breed dogs and cats can function very well with this procedure, however, medium to large breed dogs have an inconsistent outcome with this procedure. If a poor outcome is experienced with a femoral head ostectomy, a second surgery such as a total hip replacement is extremely difficult.