Distal rotational alignment of the Chinese femur and its relevance in total knee arthroplasty.

The rotational alignments of the distal femur in southern Chinese subjects were investigated. Chinese femurs are significantly more externally rotated. This is new evidence to suggest a racial difference in the distal femoral geometry. During total knee arthroplasty, a common recommendation is to allow 4 degrees of external rotation. The clinical significance of our study is that this need to be modified to 6 degrees for Chinese women and 5 degrees for Chinese men. This racial difference can be incorporated into a new concept of "a mountain and a molehill." This concept is presented in this report.