CLINICAL ORTHOPAEDICS AND RELATED RESEARCH Number 406, pp. 141–147 © 2003 Lippincott Williams & Wilkins, Inc. 141 A retrospective study of 103 knees (88 patients) who had primary total knee arthroplasty with a flexion contracture ranging from 20 to 60 was done to tabulate the primary soft tissue struc- tures released during surgery and to identify any residual deformity. The average flexion contrac- ture preoperatively was 27.1 8 and postoper- atively was 2.7 3.4 (range, 0–10). The aver- age followup was 70.4 months (range, 12–180 months). Only medial or lateral soft tissue bal- ancing procedures were necessary to correct the flexion contracture in 37 knees (35.9%) and no medial or lateral release was necessary in 25 knees (24.3%), of which 16 had a balanced poste- rior cruciate ligament. The posterior capsule was released on the deformity side of the knee in 15 knees (14.6%) and on the opposite side of the de- formity in seven knees (6.8%). The posterior cru- ciate ligament was balanced in 21 knees (20.4%) and was released in four knees (3.9%). For all knees in which the posterior cruciate ligament was released or balanced, it was done for exces- sive rollback and tightness in flexion and not for flexion contracture management. In two patients (2%) an additional 4 mm of distal femur was re- sected for a 45 and a 25 flexion contracture. The data suggest that a contracted collateral ligament is the most likely primary structure whose effec- tive release allows correction of the flexion con- tracture in most cases. Flexion contracture is a deformity that often needs to be addressed at the time of total knee arthroplasty. Combined varus deformity with a flexion contracture exists more often than a valgus deformity with a combined flexion contracture. Several studies have reported the natural history and outcome of flexion con- tractures after total knee arthroplasty. 1,4–7,10–13 Some authors advocate that the posterior cru- ciate ligament contributes to flexion contrac- ture of the knee and consider it a structure for release. 6 A biomechanical study suggested that the posterior cruciate ligament does not play a role in flexion contracture management of the knee and that sacrificing the structure may make the situation worse by creating an even larger mismatch between the extension and flexion space. 8 A previous retrospective clinical study reported that the posterior cruci- ate ligament was released more than 20% of the time, but was for treatment of a tight flex- ion space. 4 Greater distal femoral bone resec- tion, another common procedure for flexion Bone Resection and Ligament Treatment for Flexion Contracture in Knee Arthroplasty William M. Mihalko, MD, PhD; and Leo A. Whiteside, MD From the Missouri Bone and Joint Center, St. Louis, MO. Reprint requests to Leo A. Whiteside, MD, Missouri Bone and Joint Center, 10 Barnes West Drive, Suite 100, St. Louis, MO 63141. Phone: 314-205-2223; Fax: 314- 205-2324; E-mail: whiteside@whitesidebio.com. Received: July 9, 2001. Revised: March 4, 2002. Accepted: April 23, 2002. DOI: 10.1097/01.blo.0000030512.43495.74