Medical Device Daily National Editor

Hip resurfacing or hip replacement?

On the surface (no pun intended), this wouldn't seem to be too difficult a choice. But there's clearly more to this decision for the patient than meets the eye.

Hip resurfacing is a bone-conserving alternative to the traditional total hip replacement (THR) procedure for patients suffering from abnormalities of the hip, including osteoarthritis.

The Birmingham implant from segment leader Smith & Nephew's (Memphis, Tennessee) replaces the hip joint with a metal ball and cup. Surgeons cut away a tiny amount of the top of femur, conserving bone, vs. the more invasive total hip replacement.

As a panel discussing the question at last month's American Academy of Orthopaedic Surgeons (AAOS; Rosemont, Illinois) annual meeting in San Francisco found, the resurfacing-vs.-replacement question appeared to have no simple answer.

William Maloney, MD, professor of surgery and chair of the department of orthopedic surgery at Stanford University (Stanford, California), who chaired an AAOS media briefing panel on the subject, said the question is being asked with increasing frequency by patients coming into his and other surgeons' offices.

He said that with more information on hip resurfacing finding its way onto the Internet as well as in direct-to-consumer advertising "Patients are coming into our offices and asking for the procedure without really understanding what is involved or even if they are a suitable candidate."

Maloney noted that in its bid to gain market penetration, hip resurfacing is running into THR, which he termed "one of the most cost-effective innovations in medicine."

Panelist Robert Trousdale, MD, of the Mayo Clinic (Rochester, Minnesota), took the "pro-resurfacing" position, saying that such a process "provides reliable pain relief and function, with the benefit of preserving the femoral bone stock."

He said he will "consider" resurfacing in younger patients (under 60 years of age "young" by orthopedic reconstruction standards those who are at an end stage of their arthritic hip disease and thus would be candidates for an arthroplasty, are acceptable candidates for metal-on-metal bearing surface, have good femoral neck bone stock, and no major leg length or offset problems.

Trousdale said that, generally speaking, men seem to be better candidates than women, in part because "women tend to shy away from resurfacing."

Regardless of gender, "we have found that patients' perceptions of resurfacing ... are inconsistent with the known peer-reviewed advantages/disadvantages of the procedure," Trousdale said.

Tom Schmalzried, MD, of the Joint Replacement Institute at Othopaedic Hospital (Los Angeles), noting that hip resurfacing is much bigger in Europe than in the U.S. He said, "more than 50% of [Europe's] orthopedic surgeons do resurfacing," while in the U.S., the number is "less than 10%, but rapidly growing."

He hewed to his fellow panelists' points about the importance of patient selection, saying that "light, small women are at higher risk in hip resurfacing," because they tend not to have sufficient femoral bone neck stock to avoid fracture problems later. "The real variable is bone density," he said. "As the bone density goes down, the risk of femoral neck fracture goes up."

At an earlier orthopedic meeting in Hawaii, Schmalzried said that it is the job of physicians to distinguish which patients are better served with a total hip replacement and which would benefit more from resurfacing. "I think that the right way of thinking of this is not as competing technologies, but when is total hip in aggregate better and when is resurfacing ... better?" he said.

"The results are really, really good with total hip replacement," he said at the AAOS session, "so to back resurfacing, you need good arguments and data."

He said that one of the key outcomes for a THR patient is improvement in range of motion, and that range of motion is not something that can be improved via the resurfacing strategy.

Fellow panelist Paul Lachiewicz, MD, of the University of North Carolina (Chapel Hill), discussed the new technologies being seen in the total hip replacement space, citing cementless acetabular components, polyethylene bearing surfaces and stemmed femoral components, both uncemented and cemented.

"Those technologies will result in excellent pain relief," he said, "and [will] function for at least 10 to 15 years in the vast majority of patients."

Lachiewicz cited improved bearing surfaces, including polyethylene, ceramic and metal varieties, as well as new tantalum and titanium in-growth surfaces.

He said that with use of highly-crosslinked polyethylene, "most studies have shown 50% to 70% reduction of wear, even in younger [and thus more active] patients."

In his view, "we're in a revolution" as far as total hip arthroplasty is concerned. "THA can be used in all age groups, diagnoses, body-mass index, and the vast majority of hip shapes," Lachiewicz said. "There are no concerns about early or late femoral neck fractures, metal ions or hypersensitivity."

Unsurprisingly, he said, "I continue to use a modern stemmed THA in all my patients."

For his part, Paul Beaule, MD, of University of Ottawa Hospital in Canada's capital city, said the heightened consumer interest in the hip-resurfacing alternative is driven by such patients being "more demanding" in their expectations following hip surgery.

He said the so-called "Millennium patient" is "more focused on function post-operatively." They're "unaccepting of restrictions," and have high expectations for "lifestyle preservation," Beaule calling this "a very important part of what we do" as surgeons.

While saying that "new technology is not the answer to everything," he added that surgeons "need to re-educate themselves" to reconnect with the hip-resurfacing option.

Smith & Nephew's Orthopaedic Reconstruction division has the clear lead in the domestic hip-resurfacing sector, having received FDA approval of the Birmingham system in May 2006.

Among the big orthopedic competitors, Stryker (Kalamazoo, Michigan) expects to be nipping at S&N's heels during the first half of this year as U.S. distributor of the Cormet 2000 hip resurfacing system made by the Corin Group (Cirincester, UK). And both Wright Medical (Arlington, Tennessee) and Biomet (Warsaw, Indiana) are angling for a piece of whatever pie exists now and is likely to expand in the future.