When an arthritic or damaged hip joint is removed and replaced with an artificial joint, called a prosthesis, the procedure is termed a total hip replacement. Surgery to replace worn-out hip joints has doubled since 1980, from about 40,000 to 80,000 per year today.

The goal of hip replacement is to relieve the pain in the joint caused by the damage done to the cartilage, the smooth layer of tissue covering the bones of a joint. Usually the pain has become so severe that a person avoids using the joint, weakening the surrounding muscles and making it even more difficult to move the joint. Total hip replacement is considered if other treatment options do not relieve your pain and disability.

In an arthritic hip, the damaged "ball" in this ball-and-socket joint at the upper end of the thighbone is replaced by a metal ball attached to a metal stem fitted into the thighbone. A plastic socket is implanted into the pelvis, replacing the damaged socket. The materials used in a hip replacement are designed to enable the mechanical joint to move just like a normal joint. The prosthesis is generally composed of several types of metal and durable plastic. Plastic bone cement may be used to anchor the prosthesis into the bone. Joint replacements can also be implanted without cement when the prosthesis and the bone are designed to fit and lock together directly.

Serious complications from the surgery are rare, and when they do occur they are usually treatable. These can include:

• Infections in the wound or around the prosthesis. These can even occur years after the operation and might require additional surgery or removal of the prosthesis.
• Blood clots, which blood-thinning medications may help to prevent.
• Loosening of the prosthesis within the bone, which might require more surgery.
• Dislocation of the ball from the socket, which can be treated with a brace.
• Nerve injury, which is rare, and may improve with time.

Joint replacement surgery is successful in nine out of 10 people, according to the American Academy of Orthopaedic Surgeons. The extent of improvement will depend on how stiff your joint was before the surgery, as well as your motivation and adherence to an appropriate physical therapy regimen. Most joint replacements last 15 years or more; younger recipients might eventually need a second joint replacement. Nobody likes the thought of surgery; however, a total joint replacement sets you back on the road to an active lifestyle and can give you years of pain-free living that would not have been possible otherwise.