Preoperative Lateral Laxity in the Extensor Position and Intraoperative Medial Soft Tissue Release Affect Postoperative Ligament Balance in Osteoarthritis Knees Undergoing TKA in Women

Purpose: Adequate ligament balance is important for long-term outcomes after Total Knee Arthroplasty (TKA). We retrospectively evaluated preoperative factors and intraoperative medial soft tissue release techniques that affected adequate ligament balance after TKA for varus knee. Method: One hundred knees with Osteoarthritis (OA) in women were included. X-rays were taken preoperatively and postoperatively with varus and valgus stress in the extension and flexion positions. Knees were postoperatively, classified as stable (n=49) or laxity (n=51). Results: Factors associated with adequate ligament balance include joint inclination angle of varus at extension, and superficial Medial Collateral Ligament (sMCL) release. Postoperative ligament balance was significantly associated with preoperative joint inclination angle of varus at extension of 7°. Conclusion: Preoperative lateral laxity in the extensor position under stress X-ray and sMCL release may affect postoperative ligament balance. A 7° preoperative lateral joint inclination may be useful in predicting postoperative ligament balance.