Do men and women have different success with total knee replacement (TKR) based on anatomy? We know there are many differences in the bony anatomy of the male versus the female knee. Do these differences make a difference in outcomes or results?
These are the questions addressed by this Technology Overview. This summary document is from the American Academy of Orthopaedic Surgeons (AAOS). They state clearly that they are not making recommendations, but providing a summary of findings in the literature. The Technology Overview is just a tool, not advice for patient treatment.
Men have larger femurs (thigh bone) compared with women. Size, height, and width of the bone are larger in men. There are anatomic differences in the patellofemoral joint. This is where the patella (kneecap) moves up and down over the femur. Details of these differences are described.
Although women have been reported to have a larger Q-angle than men, this may be related to height more than differences in anatomy. Men and women who are the same height have equal or similar Q-angles. Shorter people have higher Q-angles.
The Q-angle is measured by drawing one line from the middle of the patella to the anterior-superior iliac spine (ASIS) of the pelvis. Another line is drawn through the middle of the patellar tendon. The angle formed by these two lines is the Q-angle. Males should have a Q-angle between eight to 12 degrees. The normal female has a Q-angle between 12 to 15 degrees. Q-angles higher than 15 degrees for men and 20 degrees for women are abnormal and may cause problems.
In this report, a review of studies comparing results of men versus women was summarized. There was no proof that age, gender, or obesity are linked with functional outcomes after TKR. Overall, there were no real differences in outcomes for men versus women after TKR.
Revision rates, range of motion and scores on tests of knee function were similar between men and women. There was some evidence to suggest that women are hospitalized longer than men for this procedure. Men have a higher death rate after TKR compared with women.