The purpose of this study is to evaluate the morphometric differences of distal femoral cut surface between Korean males and females in total knee arthroplasty.

A total of 696 patients (1,008 knees: male 92, female 916) who underwent TKA using NexGen® legacy posteriorstabilized (LPS) (605 knees: male 41, female 564) and PS ADVANCE® medical pivot knee (MPK) (403 knees: male 51, female 352) implants were analyzed prospectively. After distal femoral resection, the mediolateral width (ML) was measured at four points (anterior [Ant], distal anterior [DA], distal posterior [DP], and posterior [Post]) and compared with the ML width of the implant respectively. The aspect ratio (AR=ML/anteroposterior width) and width ratio (WR=Ant ML/DP ML) were calculated. Differences in AR, WR, and fitness between male and female were analyzed.

The AR of males was larger than that of females for both LPS and MPK; however, no differences in the WR were observed between males and females. The WR in MPK was larger than that in LPS. For both LPS and MPK, females showed greater anatomical fitness than males, and males had relatively greater incidence of undersize than females. For MPK, there were relatively more cases of overhang in Ant and DA cut surface. These results were consistent with the fact that the WR of implant in MPK was larger than that in LPS.

Korean males tend to have larger AR and less anatomical fitness of the femoral component than females because of undersize. No difference in WR was observed between Korean males and females. However, the cut surfaces as well as femoral implant of MPK had larger WR than those of LPS. MPK has more overhang on the anterior cut surface than LPS, due to a wider Ant flange (larger WR) of the implant.