Purpose. To identify factors related to knee flexion after total knee arthroplasty in a Chinese population. Methods. Records of 242 total knee arthroplasties were retrospectively reviewed. The parameters evaluated were age, gender, diagnosis, preoperative knee flexion and extension, preoperative flexion arc, tibiofemoral angle, Knee Society knee score and functional score, and implant design. Results. Advanced age, female gender, and good preoperative flexion and flexion arc were related to better postoperative flexion. Postoperative flexion tended to migrate to the middle range despite different ranges of preoperative flexion. Preoperative tibiofemoral malalignment had no significant effect on postoperative flexion. Conclusion. Contemporary designs of posterior stabilised prostheses with right and left femoral components were superior to older designs.