This study included 80 primary total knee arthroplasties due to osteoarthritis. The patients were randomized according to the type of wound closure: extension group for full extension and flexion group for 90° flexion. The incision of articular capsule was marked for precise wound alignment. In the flexion group, the knee was kept in high flexion for 1 to 2 min after wound closure. The two groups were treated with the same postoperative rehabilitation exercises. The range of motion (ROM), visual analogue scale (VAS) score of anterior knee pain, Knee Society Score (KSS) and postoperative complications were assessed at 6 weeks, 3 months and 6 months, postoperatively.