Knee Replacement Risks Higher Among Men

Reasons are unclear why men have more complications than women after knee surgery.


More than 700,000 total knee replacement (TKR) surgeries are performed in the United States each year, according to the Centers for Disease Control and Prevention – and most are done successfully. In fact, the American Academy of Orthopaedic Surgeons estimates the rate of serious complications is less than 2 percent.

Yet when complications such as infection, joint failure and heart attack do occur, they’re more likely to affect men, research finds. What investigators want to know is—why don’t men do as well following knee replacement surgery?

The Knee Replacement Disparity

A study presented at the 2015 Annual Meeting of the American Academy of Orthopaedic Surgeons (AAOS), also found that men had worse knee surgery outcomes. Men were much more likely to have a heart attack, infection, or to need revision surgery after the procedure than women.

A 2013 study published in Arthritis Care & Research examined data from about 18,000 knee replacement surgeries performed in Pennsylvania during a one-year period. The average age for both men and women in the study was 69. Study authors reported that men had a 48 percent higher risk of dying from any cause after one year, as well as a 31 percent higher risk of wound infection. Men were also 25 percent more likely to be readmitted to the hospital within 30 days, and the five-year revision rate – surgery to repair or replace the joint implant within the first five years – was 20 percent higher in men than in women.

“We found that…the relative risk rates were higher in men compared to women. I would not interpret this as TKR being riskier in men. Rather, that certain – but not all – complications may be slightly higher in men than women,” says study co-author Jasvinder Singh, MD, a practicing rheumatologist and associate professor of medicine at the University of Alabama at Birmingham School of Medicine.

The authors suggest men may have a higher five-year revision rate because of differences in knee biomechanics and a higher level of physical activity. And the increased risk of mortality, they write, “likely reflects the gender-specific cardiovascular disease mortality advantage for women.”  

Why Do Men Fare Worse Than Women?

“It’s possible more men are involved in heavy work or heavy exercise,” says R. John Wright, MD, attending orthopaedic surgeon at Brigham and Women’s Hospital in Boston. What’s unclear is whether men’s weight might be an issue, or if they are less compliant than women after their surgeries—for example, by not following their prescribed physical therapy program.

With the rate of TKRs expected to soar through 2030, “…there is much to learn about improving outcomes after TKR in patients,” says Dr. Singh.

“In practical terms, this means men may need to be watched more closely in the follow-up period,” he adds. “A more reasonable approach might be to investigate the underlying reasons for this disparity, and [develop] strategies to address those [reasons] to improve outcomes.”

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