AAOS: New Research Shows Hip, Knee Replacements Skyrocketing, Plus the Efficacy of Gender Implants and Hip Resurfacing
BY LAUREN UZDIENSKI, MARCH 12, 2008
Clinical research presented at AAOS's annual meeting included a number of large-joint studies, one of which showed that hip and knee replacement procedures will climb to 572,000 and 3.4 million, respectively, in 2030. That's 101% more hip replacements and 525% more knee replacements than were performed in 2005. The researchers are attributing the increase to an aging population, younger patients, better diagnosis and treatment options and increased arthritis in the general population, which is exacerbated by the obesity epidemic.
One of the problems created by this demand for orthopedic procedures is a forecasted dearth of surgeons. Despite the rapid growth in patient populations, the number of orthopedic surgeons is expected to grow by only 2% between 2000 and 2020, which could compromise patient access to a needed procedure.
Other data to emerge at the conference involved a study into the efficacy of gender-specific devices. Two large prospective studies found that standard hip and knee arthroplasty implants provided the same benefit for women as men, which challenges the need for popular gender-specific implants. In one study, women were no more likely than men to need revision surgery or have lower functional improvement after standard implant hip replacement; in another study, knee replacement outcomes were at least as good in women as men for pain improvement, satisfaction, need for revision and incidence of infection. Overall, the studies suggested that long-term, "outcomes with standard gender-neutral implants appeared better for women than men." Many companies manufacture or are developing gender-specific devices, a segment that is propelled largely through DTC advertising, though more data is clearly needed to justify the higher costs of these devices.
Hip resurfacing was the subject of a randomized trial where patients who received the procedure were significantly more likely to return to work and sports and had better step and hop test scores than standard arthroplasty patients did. However, functional scores and range of motion were no better than with THA, which suggested that the benefits of resurfacing were not as significant as researchers expected. The study's authors suggest that previous perceived benefits over THA resulted from a bias in patient selection, pointing out that resurfacing patients were generally younger, more active, healthier and expected a more active life after surgery. Companies who manufacture the devices as well as surgeons have said that patient selection is key to successful outcomes, so the data is not necessarily a surprise, though it remains to be seen whether resurfacing's relative benefits will be reduced as the procedure becomes more and more common in practice. For future research, long-term data into revision rates would provide additional insight into the risks and benefits of resurfacing over THA. In this active segment of large-joint reconstruction, there are challenges as to how patient needs will be met, from developing and identifying the most effective procedures to having access to surgeons who can perform them.
