Croix Bleue du Québec

Articular surface replacement may last longer and be easier to replace if it fails

A new form of hip replacement that avoids many of the problems of traditional surgery has been introduced to North America by surgeons at the Jewish General Hospital in Montreal.

Articular surface replacement (ASR), in which only the diseased portion of the hip joint is removed, is described as a less invasive alternative for arthritic baby boomers eager to get back on the tennis courts rather than sit around taking it easy.

"ASR hip resurfacing is a new technology that can benefit certain patients far more than the traditional hip replacement, allowing them to recover more quickly, be more active and achieve a more natural range of motion," says Dr. John Antoniou, an orthopedic surgeon at the hospital.

"It is suitable for the kind of patient who has no cartilage left and is quite debilitated by underlying arthritis but who has normal hip structure. The patient loses less bone and retains more of the natural hip biomechanics and balance."

Hip resurfacing involves reshaping the head of the femur, or thigh bone, rather than removing it, and capping it with a metal cup held in place with a short metal pin no thicker than the average wallboard screw.

Traditional hip replacement involves cutting off the femoral head altogether and boring deep into the femoral canal. Large amounts of bone are lost so that a six- to nine-inch hip stem, at least one inch in diameter at its thickest part, can be inserted.

"The major drawback to traditional hip replacement is that the longevity of the implant is limited to 15 to 20 years. Then the ability to redo the surgery depends on whether bone that is left is strong enough to take an even bigger stem."

The ASR implant is believed to have a wear life of up to 35 years, but the device is too new for any long-term data to be available.

If the implant fails, however, surgery to replace it is much simpler than redoing a standard hip replacement. But Antoniou cautions the initial ASR procedure is more technically demanding for the surgeon. "It is slightly riskier than traditional hip replacement surgery."

He says the procedure will probably be adopted by other hospitals in Canada. The implant has not yet been licensed here and is being used through a special access program on a patient-by-patient basis.

© 2004 The Medical Posting