Hip Replacement Failure: Is it Sex-Related?
By Emily Farr, Ivanhoe Health Correspondent
ORLANDO, Fla. (Ivanhoe Newswire) -- Total hip replacement, also called total hip arthroplasty (THA), is more often performed in women than in men. Now, new research is suggesting that women have a higher risk of implant failure too!
Researchers at the Southern California Permanente Medical Group, San Diego examined the relationship between sex and short-term risk of THA revision. A total of 35,140 patients that have a THA with three years of median follow-up were identified in a study population, which 57.5 percent of the patients were women and the average age for the patients were 66 years. They were enrolled in a total joint replacement registry from April 2001 through December 2010.
"In our analyses of a large THA cohort, including a diverse sample within 46 hospitals, we found that at the median follow-up of 3.0 years women have a higher risk of all-cause (HR [hazard ratio], 1.29) and aseptic (HR, 1.32) revision but not septic revision (HR, 1.17)," Maria C.S. Inacio, MS, and colleagues were quoted as saying.
Women received 28-mm femoral heads, 28.2 percent compared to 13.1 percent of men. Also, 60.6 percent of women had metal on highly cross-linked polyethylene-bearing surfaces, compared to men who only had 53.7 percent.
Men did have a higher proportion of 36-mm or larger heads, 55.4 percent compared to 32.8 percent of women. They had 19.4 percent metal-bearing surfaces, compared to 9.6 percent of women. At the five-year follow-up, implant survival was 97.4 percent. Device survival for men was 97.7 percent and women was 97.1 percent. After adjustments, the hazard ratios for women were 1.29 for all-cause revision, 1.32 for aspectic revision, and 1.17 for septic revision.
"The role of sex in relationship to implant failure after total hip arthroplasty (THA) is important for patient management and device innovation," study authors stated.
However, Marc Hungerford, MD, Director of Joint Replacement and Reconstruction at Mercy Medical Center in Baltimore, believes that this study demonstrates a difference between a statistical study and a clinical one.
“Clinical studies bring relevance to treating and creating new ways to go about treatment. Statistical studies may or may not be clinically relevant. Even in the sample of 35,000, the difference is tiny. It is less than half of a percent,” Hungerford told Ivanhoe.
Dr. Hungerford believes that there is more to it than just the role of gender.
“Women have smaller hips and are more at risk for hip dysplasia, making operation more difficult. There are all kinds of factors other than gender,” Hungerford concluded.
SOURCES: JAMA Internal Medicine, February 2013 and interview with Mark Hungerford, MD, Director of Joint Replacement and Reconstruction at Mercy Medical Center in Baltimore