Surface Replacement (Hip)
Surface replacement is a type of hip replacement where the socket is replaced much like a total hip, but the femoral head (ball of the hip joint) is machined to accept a metal cap that sits on the ball. The reported advantages of this technology are less femoral bone loss and an easier revision on the femoral side if that became necessary. Surface replacements have been around for over 30 years and are currently in their third generation of design.
The first two generations included a metal cap on the ball articulating with a polyethylene socket. The failure rates with the earlier implants were much higher than with total hip technology of the time and they were largely abandoned in the 1980s. The newer generation of this type of hip has a metal socket, thus creating a large metal on metal bearing. While this should eliminate some of the problems with the earlier generations of hip resurfacing, there remains a question of the long-term functionality for patients with hip disease.
Studies outside of the United States have suggested satisfactory five to eight-year results in males less than 55 years of age with otherwise normal bones. Complications have been higher in women in general and in older men. Because we have to retain the femoral head during the procedure, the surgery requires a longer incision and more soft tissue dissection than a standard total hip replacement. At this time, it is unclear what the long-term benefits of this procedure will be and it is reserved for use in only selected candidates at this time.