In the midst of the furor surrounding metal-on-metal hip implants, a recent study of U.S. implant recipients found that these implants—as well as implants made from other materials—are even more likely to fail in women than in men. In fact, women overall were 29% more likely to require a revision surgery within the first three years following their initial hip implant. Even though women comprise the majority of the 400,000 annual hip replacement surgeries each year, the studies showed no clear answer as to which type of hip implants perform the best in women.
The Need for More Research
Hip implants are generally performed as a response to pain and loss of mobility, whether caused by advancing arthritis or injury. Diana Zuckerman, president of the National Research Center for Women and Families, stated that not only could research regarding women and hip implants save literally billions of dollars, such research could also prevent female patients from the necessity of undergoing risky revision surgery. The recent study followed 35,000 surgeries across 46 hospitals in the Kaiser Permanente health system with results published in JAMA Internal Medicine. It is worth noting that this particular study was funded by the FDA.
Life Expectancy of Hip Implants
While ceramic and polyethylene hip implant devices are expected to last from eight to possibly twelve years, the metal-on-metal hip implants were expected to last well over fifteen years. Yet after only three years post-implant, 2.3% of the women and 1.9% of the men had to undergo revision surgery to fix a problem associated with the original hip replacement such as infection, loosening, instability and broken bones. An epidemiologist in San Diego considers those numbers “still a very small number of failures,” although it is unlikely the patients who must undergo another dangerous surgery feel the same.
Potential Reasons for Increase in Revision Surgeries among Women
Perhaps one of the reasons for the increased failure rate among women has to do with the fact that most women have smaller joints and bones than men. Because of this physical disparity, women require hip implants with smaller femoral heads, yet those smaller heads are more likely to dislocate, requiring revision surgery. Another potential reason for the increase in revision surgeries for women could have to do with a higher loss of bone density among women as compared with their male counterparts.
Why Women Might Want to Avoid an All-Metal Hip Implant
The failure of the metal-on-metal hip implants among women was nearly twice that of the same all-metal implants in men. Zuckerman cautioned women considering an artificial hip implant to stay with a model which has been on the market for a significant number of years with few problems. The metal-on-metal hip implants have shown a considerably higher failure rate than their ceramic and polyethylene counterparts with several manufacturers of the all-metal devices being forced to issue recalls. The metal parts of the hip implant can rub against one another when the recipient of the implant walks, runs, or engages in other activities. This friction can cause tiny metal particles to lodge in surrounding tissues or enter the bloodstream causing a wide array of serious medical problems for the recipient.