“The results in men are better than women. [The study] tries to explain it by size, but I don’t think that’s a complete explanation,” Dr. Su continues.

He says he feels more research is needed in this area to better answer this question.

Some Devices Have Higher Failure Rates

As studies have noted higher failure rates with certain kinds of hip resurfacing systems, one proposed explanation for the differences was that surgeons weren’t adequately trained to work with them.

But the Australian study refutes that notion, with analysis showing higher failure rates associated with certain kinds of components, regardless of the surgeons’ training and experience with them.

After 11 years, the Australian study found that of the three most commonly used implants, the ASR and the Durom have a significantly higher risk of revision than the Birmingham hip resurfacing system.

The ASR hip resurfacing system has recently been taken off the worldwide market, and DePuy, the company that makes the implants warned doctors this week about the possibility of early failure rates.

And in July 2008, Zimmer, the company that makes the Durom parts, said that it would temporarily halt sales of that product in the U.S. while they offered doctors additional training.

The Durom system has been implanted in patients in the U.S. in clinical trials, The Food and Drug Administration (FDA) has not yet approved it for general use. 

Dr. Della Valle says this research can be confusing to patients and in the end, he believes, the choice between a total hip replacement and hip resurfacing depends more on the individual than anything else.

“It really has to be somewhat customized in terms of what the patient wants because there are some very active 65-year-olds who want to run and do sports, and if their bone quality is good, I think they could be a candidate for hip resurfacing,” Dr. Della Valle explains.

“I would hate to see the technology written off, because it works well in some patients, and those are some of my happiest patients,” he continues. “But for the majority of patients, a conventional total hip replacement will be associated with a lower risk of complications and problems than resurfacing. But there is a segment of the population that benefits from the technology and has an equivalent or lower risk of revision.”

How Components Are Secured Also Affects Implant Survival

In a second study, researchers in Finland, drawing on data from that country’s joint replacement registry, found that the way components are applied to the bone – either with or without cement adhesives – appears to affect the lifespan of total hip replacements in younger patients.

They studied 4,032 cases of primary total hip replacements done on patients younger than age 55 with osteoarthritis. They found groups that had used so-called cementless stems had an 89 or 90 percent survival rate compared to cemented stems at 72 percent. Cementless cups had an 80 percent survival rate compared to 71 percent for cemented cups.

“It shows that cemented fixation is no longer the gold standard. We think we knew it but it’s nice to have confirmation,” Dr. Su says. “It continues to show that this age group, the younger age group, is challenging and we need to continue to prove outcomes in that age group.”

Dr. Della Valle agrees and says he finds these results interesting because most European countries have continued to use cemented procedures. But about 15 years ago he says most North American surgeons shifted from cemented to cementless, finding the technique easier and believing it gave the implant more flexibility.

“In North America it was a very rapid switch from cemented to cementless,” Dr. Della Valle says. “It was really almost a wholesale overnight switch, and it’s comforting to know that now there’s data from outside the U.S. that suggests that’s a good decision.”