Improved materials, techniques for hip resurfacing may correct past problems

OrthoSupersite—May 11, 2009   

There has been a resurgence in hip resurfacing during the last decade. According to Edwin P. Su, MD, Hospital for Special Surgery, the modern generation of metal-on-metal hip resurfacing has improved upon the problems of the past through better implant designs and materials, instruments and surgical techniques.

“This has lead to improvement in the survival curve at [the] mid-to early-follow-up to about 97%,” he said during his presentation at the 5th Annual Current Concepts in Joint Replacement Winter Meeting.

Design, materials

While there are more than 10 different hip resurfacing devices available internationally, Su noted that most designs incorporate a femoral component with a short stem for femoral cement fixation and press-fit acetabular fixation.

Su noted that the implant materials have also improved, and that metal-on-metal devices eliminate the problem of polyethylene debris. “There is a better understanding for metallurgy and that there is a need for high carbide cobalt chromium bearing materials,” he said. “The manufacturing tolerances themselves have also been improved.”

In addition, surgeons now have better instruments for performing hip resurfacing. “Although the surgeons of the past did understand the concepts of preparing the bone and putting it into slight valgus orientation, they had a limited ability to do that with the instruments of the day,” Su said. Today, surgeons have various component sizes which allow them to save bone on both the femoral and acetabular sides.

Instrumentation

He also noted that intraoperative guides have improved and incorporate devices to measure and align the femoral neck. These guides also help surgeons achieve accurate component position and avoid notching the femoral neck.

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