The American Academy of Orthopaedic Surgeons (AAOS) recently did a review of studies comparing men and women with total knee replacements (TKRs). They asked two questions: 1) Who has a higher failure rate after traditional TKR: men or women? 2) Does having a specific knee replacement for women increase the rate of success?
They found that even with many of the anatomic differences between men and women, the results of traditional TKR was not different between the two sexes. Range of motion and scores on tests of knee function were similar. Some studies reported that women have lower rates of failure from wear and tear over time. The need for implant removal or revision was equal between men and women.
There were no studies of gender-specific TKRs. This is an area for future research. A gender-specific total knee replacement implant is a prosthesis that is designed either for a male or a female. The size of the implant is slightly different. It is built to make adjustments for the differences in sizes and anatomy of the bones between genders.
It's possible the results in your family are just by chance. But there could be an anatomical trait that lends itself to poorer results compared with men. Other factors include type of implant, surgical technique used, and surgeon's experience. There may have been differences in the rehab program used with the women compared with the men. Attitude and compliance may also have affected the outcomes.