The purpose of this study was to determine the effects of preoperative, intraoperative, and postoperative intervention on the incidence of loss of motion (LOM) following ACL reconstruction. A retrospective review of patients undergoing ACL reconstruction between 1990 and 1991 was conducted to identify those with LOM. Factors potentially related to loss of motion were recorded. The results were compared to the findings of a similar group of patients who underwent ACL reconstruction between 1987 and 1989. In 1990 to 1991, less concomitant ligament surgery was performed, the incidence of loss of extension was significantly reduced, and the incidence of loss of flexion was significantly increased. It appears the risk for loss of extension can be minimized by delaying surgery following acute injury, performing less concomitant ligament surgery, paying meticulous attention to notchplasty and anatomic placement of the graft, and placing early emphasis on restoration of full extension following surgery.