Mahoney O M, Noble P C, Rhoads D D, Alexander J W, Tullos H S
Department of Orthopaedic Surgery, Baylor College of Medicine, Houston, Texas.
J Arthroplasty. 1994 Dec;9(6):569-78. doi: 10.1016/0883-5403(94)90110-4.
The strain developed in the posterior cruciate ligament (PCL) of eight fresh cadaveric knees was measured before and after total knee arthroplasty using a loading technique that simulated stair ascent and descent. Each knee was instrumented with a Hall Effect strain gauge (Micro-Strain, Burlington, VT) in the PCL, a load cell in the quadriceps tendon, an electrogoniometer, and an array of linear displacement transducers to measure femoral rollback. Testing was undertaken with each knee in its normal state with the anterior cruciate cut and with a cruciate-retaining prosthesis, a cruciate-excising prosthesis, and a cruciate-substituting prosthesis. Normal PCL strain levels were produced in only 37% of the trials following implantation of the cruciate-retaining knee arthroplasties. With a cruciate-retaining prosthesis, femoral rollback decreased by an average of 36% and was associated with a 15% loss in extensor efficiency. In the procedures performed with excision of the PCL, rollback decreased by 70% and extensor efficiency by 19%. Cruciate substitution resulted in a 12% loss in rollback and an 11% decrease in extensor efficiency. The strain developed within the PCL during knee flexion was found to be extremely sensitive to the thickness of the polymeric tibial insert. In the majority of cases, it was not possible to restore normal ligament loading with flexion while simultaneously maintaining acceptable varus/valgus stability of the knee joint. Using a range of contemporary knee arthroplasties, the authors were unable to consistently reproduce normal function of the PCL.
采用模拟上下楼梯的加载技术，测量了8个新鲜尸体膝关节在全膝关节置换术前、后的后交叉韧带（PCL）应变。每个膝关节在PCL中安装一个霍尔效应应变片（Micro-Strain，伯灵顿，佛蒙特州）、股四头肌肌腱中的一个测力传感器、一个电子测角仪以及一系列线性位移传感器，以测量股骨后滚。对每个膝关节在正常状态、前交叉韧带切断状态以及使用保留交叉韧带假体、切除交叉韧带假体和替代交叉韧带假体的情况下进行测试。在植入保留交叉韧带的膝关节置换术后，仅37%的试验产生了正常的PCL应变水平。使用保留交叉韧带的假体时，股骨后滚平均减少36%，且伸肌效率损失15%。在进行PCL切除的手术中，后滚减少70%，伸肌效率降低19%。交叉韧带替代导致后滚损失12%，伸肌效率降低11%。发现膝关节屈曲时PCL内产生的应变对聚合物胫骨衬垫的厚度极为敏感。在大多数情况下，在保持膝关节可接受的内翻/外翻稳定性的同时，不可能通过屈曲恢复韧带的正常负荷。使用一系列当代膝关节置换术，作者无法始终如一地重现PCL的正常功能。
