Men play post-op catch-up

Although women generally have worse knee function and more severe symptoms before undergoing surgery for knee replacement than men, they recover faster after the operation. Men take longer to recover but, after a year, they catch up with women and there are no differences in surgery outcomes at that time. These findings by Thoralf Liebs, from Hassenpflug University of the Schleswig-Holstein Medical Center in Germany, and colleagues, are published online in Springer's journal Clinical Orthopaedics and Related Research.

Although research to date shows conflicting results, anatomic, social and cultural differences are thought to explain gender-specific function and health-related quality of life after total knee replacement surgery, or knee arthroplasty. Also highly debated are gender-specific total knee arthroplasty implants to account for relatively small anatomic differences. The rationale behind their respective designs is that there are specific anatomic differences; for instance, women tend to have slightly narrower knees than men.

To determine whether women are worse off than men after knee replacement operations, Liebs and his coauthors analyzed data from three German multicenter trials. The data evaluated rehabilitation measures after standard unisex knee arthroplasty in 494 patients - 141 men and 353 women. The authors looked at self-reported physical function three, six, 12 and 24 months after surgery as well as leg-specific stiffness and pain.

Women were on average three years older than men at the time of surgery and were more physically limited and in greater pain than men. At three and six months after surgery, women showed greater improvements in function, and reduced pain than men. When the authors took age, BMI (body mass index) and co-morbidities into account, the gender difference remained at three months after surgery but not at six months.

The authors concluded: "We do not know yet why women recover faster from surgery than men. It could be because of women's lower preoperative health-related quality of life, whereby they have more to gain from surgery, or because of other speculative factors such as different postoperative activity levels, psychological factors, or different utilization of treatment. It is too early to say."