Anthropomorphic differences between the distal femora of men and women

There is debate about whether distinct designs of femoral components for men and women are needed based on morphologic and size differences between genders. We asked whether anthropomorphic differences exist between the distal femoral dimensions in women and men. We measured the distal femora of 100 women and 100 men intraoperatively after preparation for prosthetic implantation. The measured dimensions included the anteroposterior height from the posterior edge of the medial femoral condyle to the flush anterior cut, the mediolateral width at the transepicondylar axis, the anterior and posterior edges of the anterior chamfer, and the medial and lateral trochlear flanges. These measurements were compared between genders using independent-samples t test. The aspect ratio (a measure of the shape of the distal femur), the ratio between the anteroposterior and mediolateral dimensions, was calculated for men and women to determine whether there is a shape difference between genders. The mean aspect ratio was larger for women than for men (0.84 [range, 0.57-1.03] versus 0.81 [range, 0.066-1.34], respectively). The standard deviation and range of each measurement of size and morphology suggest variability not only between genders but also within genders. Whether the aspect ratios and variations will reflect clinically important differences in outcomes after TKA with available prostheses will require additional study.