Tezuka T, et al. - Authors assessed the changes in femoral rotation after total hip arthroplasty (THA), and gauged the preoperative patient factors that influence femoral rotation after THA. One week after THA, femoral rotation angle showed the mean internal change of 4.6°. Findings suggested an association of sex, age, preoperative anatomical femoral anteversion and preoperative femoral rotation with postoperative femoral rotation. An externally rotated femur after THA was seen in the patients who were male, older, and who exhibited lesser preoperative anatomical femoral anteversion or greater preoperative femoral rotation angles. On the contrary, an internal rotation of the femur after THA was noted in the patients who were female, younger, and who exhibited greater preoperative anatomical femoral anteversion or lesser preoperative femoral rotation angles.