Morphological measurement of the knee: race and sex effects

Three-dimensional knee models of 148 Chinese (61 males, 87 female) and of 127 Caucasian (79 male, 48 female) were constructed. The anteroposterior (fAP, tAP) and mediolateral (fML, tML) dimensions of cross-section of the femur and tibia after simulated TKA bony resection were measured. Females have smaller femoral aspect ratios (fML/fAP) than males (Chinese: 1.22 +/- 0.05 vs 1.29 +/- 0.04; Caucasians: 1.18 +/- 0.05 vs 1.25 +/- 0.05) (P < 0.05). The tibial aspect ratios (tML/tAP) of the Chinese males (1.56 +/- 0.07) and the Caucasian females (1.54 +/- 0.07) are smaller than that of the Caucasian males (1.61 +/- 0.08) (P < 0.05). In regression analysis, for the same fAP or tAP dimension, females have narrower femoral condyles or tibia platforms than males; the Caucasian males have narrower femoral condyle or wider tibial platform than the Chinese males. For the same fAP dimension, males have lager tibial platforms than females; the Chinese males have larger tibial platforms than the Caucasian males. Racial and sex differences of the resected femur and tibia surfaces were found between a Chinese population and a Caucasian population. The relationship between the femur and tibia also showed racial and sex differences. These results may provide guidelines for future development of sex-specific as well as race-specific total knee replacement surgeries.