Intraoperative medial collateral ligament (MCL) injury during total knee arthroplasty (TKA) is a serious complication. External bracing and/or conversion to a constrained implant has previously been studied. The technique of using an internal high-strength suture brace to augment an MCL repair has been evaluated in the nonarthroplasty patient and could provide an alternate solution. The goal of this study was to determine whether MCL repair with internal suture bracing restores stability of the implanted knee joint. A robotic simulator completed laxity testing on 5 cadaveric knee specimens in 4 sequential phases: (1) intact knee, (2) after implantation with TKA, (3) after sectioning of the MCL, and (4) after MCL repair with suture brace augmentation. Laxity was compared between the different test phases throughout range of motion. Subsequently, the internal brace was tested to failure under valgus load. The MCL repair with internal bracing was effective at restoring laxity in varus-valgus, internal-external, and me-dial-lateral degrees of freedom through midflexion, with limited support at deeper flexion angles and in anterior-posterior laxity. Rotational laxity was not significantly different than intact knee laxity. Generally, medial-lateral translations were less and anterior-posterior translations were greater and were significantly different at 30° to 45° and 90°, respectively. The mean failure moment was 46.4±9.1 Nm, with the primary mode of failure being MCL repair. Primary MCL repair with internal bracing using a high-strength suture augment showed the potential to provide adequate stability and strength to correct MCL incompetence in TKA without the use of an external knee brace or constrained implants. [Orthopedics. 202x;4x(x):xx–xx.]

全膝关节置换术（TKA）期间的术中内侧副韧带（MCL）损伤是一种严重的并发症。先前已经研究了外部支撑和/或转换为约束植入物。使用内部高强度缝合支架来增强 MCL 修复的技术已在非关节成形术患者中进行了评估，并且可以提供替代解决方案。本研究的目的是确定使用内部缝合支撑修复 MCL 是否可以恢复植入膝关节的稳定性。机器人模拟器在 4 个连续阶段完成了 5 个尸体膝关节样本的松弛度测试：(1) 完整膝关节，(2) TKA 植入后，(3) MCL 切片后，以及 (4) MCL 缝合支架增强修复后. 在整个运动范围内比较不同测试阶段之间的松弛度。随后，内部支架在外翻载荷下被测试失效。带有内部支撑的 MCL 修复可有效恢复通过中屈曲的内翻-外翻、内-外和内侧-外侧自由度的松弛，但在更深的屈曲角度和前后松弛时的支撑有限。旋转松弛与完整膝关节松弛没有显着差异。一般来说，内侧-外侧平移较少，前后平移较大，分别在 30° 至 45° 和 90° 处有显着差异。平均故障力矩为 46.4±9.1 Nm，主要故障模式为 MCL 修复。使用高强度缝合增强的内部支撑进行的初级 MCL 修复显示了在不使用外部护膝或约束植入物的情况下提供足够的稳定性和强度来纠正 TKA 中 MCL 功能不全的潜力。[骨科。202x;4x(x):xx–xx.]