Hip Replacement Surgery

According to the American Association of Orthopaedic Surgeons, more than 200,000 hip replacements are performed each year. Of these, osteoarthritis accounts for the majority of patients needing a hip replacement operation. The condition, affecting about 30 million Americans, occurs when cartilage on the end of bone begins wearing away, causing pain and stiffness. But when the cartilage wears away completely, the bones rub directly against each other and hip replacement is needed.

Other degenerative hip diseases leading to the need for hip replacement surgery include avascular necrosis, a condition where the head of the femur loses some of its blood supply and actually dies. Hip fractures as well as some types of hip conditions that appear in childhood can also lead to degeneration many years after an injury and require the need for hip replacement surgery. In a problem hip, where the cartilage has worn away, the joint bone becomes rough and pitted, resulting in pain and limited range of motion.

The physicians at Cedars-Sinai Orthopaedics are consistently striving to develop new technologies, instrumentation and techniques for hip replacement surgery. This leads the way to more accurate outcomes, shorter hospital stays, faster recovery and less pain. Several types of hip replacement surgery procedures are detailed below.

Total Hip Replacement: A Minimally Invasive Procedure

Benefits of the minimally invasive procedure typically include:

• Patients experience less pain after surgery due to less manipulation and more precise placement
• Eliminates the amount of cutting we have to do to replace the hip joint, patients recover more quickly
• Hospital stay is typically two days versus four to six days
• Less time is need for rehabilitation therapy
• Return to work and normal activities usually within a couple of weeks versus up to month or more

With traditional hip replacement, surgeons cut a six to 12-inch incision along the thigh, cutting through the muscle and tendon, to reach the hip joint, causing more blood loss. In addition, surgeons performing traditional hip replacement must dislocate the hip by pulling the leg into an extreme position, which causes additional soft tissue trauma.

Although the hip replacement procedure represents a major advance in minimally invasive surgery, it is not recommended for patients who are obese, have osteoporosis, or who have severe bone deformities. Further, the procedure is complex, requiring surgeons to undergo special training and takes time for them to learn. This surgery offers an exciting option for many patients requiring hip replacement, particularly young, active working people for whom it would be costly to take time off from work.

Total Hip Replacement: Traditional Procedure

With hip replacement surgery, the surgeon replaces the ball and socket portion of the hip with a metal ball and a plastic socket. Many different types of designs and materials are currently used in artificial hip joints. All of them consist of two basic components: the ball component (made of a highly polished strong metal) and the socket component (a durable plastic cup which may have an outer metal shell). The metal is usually made from chrome or titanium; the plastic from polyethylene. The artificial joint is either cemented into place or secured by the natural bone growing back in around it. Sometimes a combination of approaches is used, depending on the patient's bone structure and the surgeon's judgment.

In a cemented hip replacement, the cement acts as a grout by holding the artificial components in place. If cement is not used, the natural bone is allowed to grow into the rough surface of the prosthesis. Sometimes screws are used to fix the cup to the pelvis during the early stages of bone growth. Your orthopedic surgeon will remove the damaged cartilage and bone, then position new metal and plastic joint surfaces to restore the alignment and function of your hip.

A noncemented replacement has also been developed which is used most often in younger, more active patients. The prosthesis may be coated with textured metal or a special bone-like substance, which allows bone to grow into the prosthesis.

To prepare you for surgery, the Cedars-Sinai Orthopaedics provides a guide for your hospital stay so you understand all aspects and expectations prior to surgery. This usually leads to a faster recovery and an easier transition.

Muscle-Sparing Hip Replacement: Anterior and Posterior Methods

In traditional hip replacement surgery, the surgeon makes a long incision and cuts muscles, tendons and ligaments to get to the hip joint. When more tissues, muscles and tendons are cut during surgery, the recovery is more painful and the healing process takes longer. A muscle-sparing hip replacement surgery has been developed that has the potential to make recovery faster and less painful. During this procedure, two incisions are made in the front of the hip instead of one longer incision. The muscle is not cut at all. For the posterior method, the surgeon gets to the hip joint from the back of the hip. Muscles are also separated and not cut for less trauma to the patient.

Benefit of muscle sparing hip replacement typically include:

• Less tissue trauma—muscles and tendons are not cut
• Reduced blood loss
• Smaller incisions with less scarring—two smaller incisions, rather than one 8- to 12-inch incision
• Shorter hospital stay—one to two days versus four to five days
• Quicker and less painful rehabilitation
• Faster return to work and daily activities

The muscle-sparing procedure can be done on most patients unless they previously had hip surgery, are obese or have significant deformity of the hip.