Abstract：
OBJECTIVE: Resecting the posterior cruciate ligament (PCL) increases posterior laxity and increases the flexion gap more than the extension gap in the native (i.e. healthy) knee. These two effects could lead to significant anterior displacement of the medial femoral condyle in kneeling following total knee arthroplasty even when using a tibial insert with a high degree of medial conformity. Using an insert with ball-in-socket medial conformity and a flat lateral articular surface, the primary purpose was to determine whether the medial femoral condyle remained stable with and without PCL retention during kneeling.
METHODS: Two groups of patients were studied, one with PCL retention (22 patients) and the other with PCL resection (25 patients), while kneeling at 90º flexion. Following 3D model-to-2D image registration, A-P displacements of both femoral condyles were determined relative to the dwell point of the medial socket.
RESULTS: With PCL resection versus PCL retention, the medial femoral condyle was 5.1 ± 3.7 mm versus 0.8 ± 2.1 mm anterior of the dwell point (p < 0.0001). Patient-reported function scores were comparable (p ≥ 0.1610) despite a significantly shorter follow-up of 7.8 ± 0.9 months with PCL retention than 19.6 ± 4.9 months with PCL resection (p < 0.0001). Range of motion was 126 ± 8° versus 122 ± 6° with and without PCL retention, respectively (p = 0.057).
CONCLUSIONS: Surgeons that use a highly conforming tibial insert design can stabilize the medial femoral condyle during kneeling by retaining the PCL. In patients with PCL resection, the 9 mm high anterior lip of the insert with ball-in-socket medial conformity was insufficient to prevent significant anterior displacement of the medial femoral condyle when weight-bearing on the anterior tibia.
METHODS: Two groups of patients were studied, one with PCL retention (22 patients) and the other with PCL resection (25 patients), while kneeling at 90º flexion. Following 3D model-to-2D image registration, A-P displacements of both femoral condyles were determined relative to the dwell point of the medial socket.
RESULTS: With PCL resection versus PCL retention, the medial femoral condyle was 5.1 ± 3.7 mm versus 0.8 ± 2.1 mm anterior of the dwell point (p < 0.0001). Patient-reported function scores were comparable (p ≥ 0.1610) despite a significantly shorter follow-up of 7.8 ± 0.9 months with PCL retention than 19.6 ± 4.9 months with PCL resection (p < 0.0001). Range of motion was 126 ± 8° versus 122 ± 6° with and without PCL retention, respectively (p = 0.057).
CONCLUSIONS: Surgeons that use a highly conforming tibial insert design can stabilize the medial femoral condyle during kneeling by retaining the PCL. In patients with PCL resection, the 9 mm high anterior lip of the insert with ball-in-socket medial conformity was insufficient to prevent significant anterior displacement of the medial femoral condyle when weight-bearing on the anterior tibia.
摘要：
目的：切除后交叉韧带（PCL）会增加后松弛度，并且在天然（即健康）膝关节中，屈曲间隙比伸展间隙增加得更多。即使使用具有高度内侧整合度的胫骨插入物，这两种作用也可能导致全膝关节置换术后跪下的股骨内侧髁明显前移。使用带有球窝内侧整合和平坦外侧关节面的插入物，主要目的是确定在跪下有或没有PCL保留的情况下，股骨内侧髁是否保持稳定。
方法：对两组患者进行研究，一个PCL保留（22例），另一个PCL切除（25例），而跪在90º屈曲。在3D模型到2D图像配准之后，确定两个股骨髁的A-P位移相对于内侧窝的停留点。
结果：PCL切除与PCL保留相比，股骨内侧髁为5.1±3.7mm,位于停留点前为0.8±2.1mm(p<0.0001).患者报告的功能评分具有可比性（p≥0.1610），尽管PCL保留的随访时间为7.8±0.9个月，明显短于PCL切除的19.6±4.9个月（p<0.0001）。运动范围为126±8°，而有和没有PCL保留的运动范围为122±6°。分别（p=0.057）。
结论：使用高度一致的胫骨插入物设计的外科医生可以通过保留PCL在跪下期间稳定股骨内侧髁。在PCL切除术的患者中，当在胫骨前负重时，具有球窝内侧整合的插入物的9毫米高的前唇不足以防止股骨内侧髁的明显前移。
方法：对两组患者进行研究，一个PCL保留（22例），另一个PCL切除（25例），而跪在90º屈曲。在3D模型到2D图像配准之后，确定两个股骨髁的A-P位移相对于内侧窝的停留点。
结果：PCL切除与PCL保留相比，股骨内侧髁为5.1±3.7mm,位于停留点前为0.8±2.1mm(p<0.0001).患者报告的功能评分具有可比性（p≥0.1610），尽管PCL保留的随访时间为7.8±0.9个月，明显短于PCL切除的19.6±4.9个月（p<0.0001）。运动范围为126±8°，而有和没有PCL保留的运动范围为122±6°。分别（p=0.057）。
结论：使用高度一致的胫骨插入物设计的外科医生可以通过保留PCL在跪下期间稳定股骨内侧髁。在PCL切除术的患者中，当在胫骨前负重时，具有球窝内侧整合的插入物的9毫米高的前唇不足以防止股骨内侧髁的明显前移。
