Objective: To explore the effectiveness of one-stage posterior medial corner (PMC) repair or reconstruction combined with anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) reconstruction in treating KD-ⅢM dislocation.
Methods: The clinical data of 15 patients with knee KD-ⅢM dislocation who met the selection criteria between January 2016 and July 2019 were retrospectively analyzed. There were 9 males and 6 females, aged 22-61 years (mean, 40.3 years). Injuries were caused by violence of flexion, valgus, and external rotation, including 10 cases of traffic accident injuries, 3 cases of crush injuries, 1 case of winch injury, and 1 case of explosion injury. The time from injury to operation ranged from 3 days to 6 months, with an average of 18.5 days. PMC repair combined with PCL+ACL reconstruction was performed in 10 cases in acute stage (within 3 weeks after injury), including 3 cases of irreducible dislocation. PMC+PCL+ACL reconstruction was performed in 5 cases with chronic dislocation. Before operation and at last follow-up, the knee joint function was evaluated by Lysholm score and International Knee Documentation Committee (IKDC) 2000 score. KT-3000 was used to evaluate the forward stability of the knee (calculated the difference of tibial anterior displacement of both knees), the X-ray films of the stress position of the knee joint was used to evaluate the valgus of the knee (calculated the difference of medial joint space width of both knees) and the backward stability (calculated the difference of tibial posterior displacement of both knees), and the internal and external rotation stability was evaluated by knee flexion 30° tibial external rotation and knee flexion 90° tibial internal rotation tests (calculated the difference of tibial internal rotation and the difference of tibial external rotation of both knees).
Results: The operation time was 120-240 minutes, with an average of 186.5 minutes. Patients were followed up 24-48 months, with an average of 27.4 months. There was no complication such as infection, deep vein thrombosis, vascular injury, or heterotopic ossification. At last follow-up, the Lysholm score, IKDC2000 score, the difference of tibial anterior displacement of both knees, the difference of medial joint space width of both knees, the difference of tibial posterior displacement of both knees, the difference of tibial internal rotation and the difference of tibial external rotation of both knees significantly improved when compared with preoperative ones ( P<0.05). According to the IKDC2000 valgus stability grading standard, there were 3 cases of grade C and 12 cases of grade D before operation, and 10 cases of grade A and 5 cases of grade B at last follow-up, which was significantly improved when compared with that before operation ( Z=-4.930, P=0.000). At last follow-up, the pivot shift tests of 15 patients were negative. The anterior and posterior drawer tests of 10 patients were negative, 5 patients had mild instability, both the anterior and posterior drawer tests were positive.
Conclusion: KD-ⅢM dislocation of the knee joint can lead to the posterior medial and anterior instability. Acute dislocation combined with "dimple sign" requires surgical reduction as soon as possible to repair PMC and reconstruct PCL and ACL. In chronic patients, PMC is difficult to repair, it is recommended to reconstruct PMC, PCL, and ACL at one stage to improve knee joint stability. The early and middle effectiveness are satisfactory.
目的: 探讨同期后内侧角（posterior medial corner，PMC）修复或重建联合前交叉韧带（anterior cruciate ligament，ACL）、后交叉韧带（posterior cruciate ligament，PCL）重建治疗膝关节KD-ⅢM型脱位的临床疗效。.
方法: 回顾分析2016年1月—2019年7月收治且符合选择标准的15例膝关节KD-ⅢM型脱位患者临床资料。男9例，女6例；年龄22～61岁，平均40.3岁。均为屈膝、外翻、外旋暴力致伤，其中交通事故伤10例，砸伤3例，绞伤1例，爆炸伤1例。受伤至手术时间为3 d～6个月，平均18.5 d。10例急性期（伤后3周内）患者行PMC修复联合PCL+ACL重建手术（包括3例不可复位性脱位）；5例陈旧性患者行PMC+PCL+ACL重建手术。术前及末次随访时采用膝关节Lysholm评分和国际膝关节文献委员会（IKDC）2000评分评估膝关节功能；使用KT-3000评估膝前向稳定性（计算双膝胫骨前移距离差值），膝关节应力位X线片评估膝关节外翻（计算双膝内侧关节间隙宽度差值）及后向稳定性（计算双膝胫骨后移距离差值），采用屈膝30° 胫骨外旋、屈膝90° 胫骨内旋试验评估内、外旋转稳定性（分别计算双膝内旋和外旋角度差值）。.
结果: 患者手术时间120～240 min，平均186.5 min。术后患者均获随访，随访时间24～48个月，平均27.4个月。未发生切口感染、深静脉血栓形成、血管神经损伤、异位骨化等并发症。末次随访时，患者Lysholm评分和IKDC2000评分以及双膝内侧关节间隙宽度差值、胫骨前移距离差值、胫骨后移距离差值、胫骨内旋角度差值及胫骨外旋角度差值均较术前明显改善（ P<0.05）。根据IKDC2000外翻稳定性分级标准，术前C级3例、D级12例，末次随访时为A级10例、B级5例，较术前显著改善（ Z=−4.930， P=0.000）。末次随访时15例患者轴移试验均（−），10例患者的前、后抽屉试验（−），5例患者存在轻度前后向不稳，前、后抽屉试验均为（+）。.
结论: 膝关节KD-ⅢM型脱位可导致膝关节后内侧及前向不稳定。脱位急性期合并“酒窝征”者需尽早手术复位，修复PMC并重建PCL+ACL；陈旧性患者PMC修复困难，建议一期手术重建PMC+PCL+ACL改善膝关节稳定性，可获得满意近中期临床随访结果。.
Keywords: Knee dislocation; anterior cruciate ligament; arthroscopy; dimple sign; posterior cruciate ligament; posterior medial corner; posterior-medial instability.