November 14 (HealthDay News) -- Age and gender are important to the success of hip resurfacing, say U.S. researchers who reviewed more than 500 surgeries and found the majority of serious complications occurred in women of all ages and men over age 55.

Hip resurfacing offers an alternative to hip replacement, in which the ball of the hip joint is removed and replaced with a metal stem inserted into the thigh bone. In hip resurfacing, the ball of the hip joint remains, but its surface is reshaped to accept a rounded cap with a short stem that sits in the thigh bone, or femur.

Study lead author Dr. Craig Della Valle, a joint reconstruction specialist at Rush University Medical Center, and colleagues looked at the first 537 hip resurfacing surgeries performed in the United States using the Birmingham Hip Resurfacing implant, approved by the Food and Drug Administration in October 2006.

Serious complications occurred in 32 of the cases, including 10 cases in which the femoral neck fractured after surgery. These types of fractures, which don't occur in hip replacements, required additional surgery.

Nine of the 10 femoral neck fractures occurred in either female patients or those older than 55. Eight of the fractures occurred in cases where the surgeon was relatively inexperienced with the procedure (10 or fewer hip resurfacing surgeries).

"Patients who are older or who are female tend to have softer bone. Also, men on average have larger bone structures, with a greater surface area for securing the implant," Della Valle explained in a Rush University news release. Males under the age of 55 are the ideal patients for hip resurfacing, the experts said.

"Patients may be eager to take advantage of technological innovations, but for older individuals, a conventional hip replacement is generally more appropriate," Della Valle advised.

The study was released online and was expected to be published in the January print issue of the journal Clinical Orthopaedics and Related Research.

SOURCE: Rush University Medical Center, news release, Nov. 3, 2008