胫骨假体旋转对线技术对髌股关节生物力学影响的实验研究

Biomechanical effect of axial rotational alignment technique of tibial component on patellofemoral in total knee arthroplasty

[目的]探讨全膝置换术中改变胫骨假体的旋转对线技术对髌股关节生物力学的潜在影响,指导术中进行正确的胫股旋转对线,以减少术后髌股关节并发症的发生。[方法]取9个新鲜冷冻人膝关节做实验,自行设计膝关节实验架,与Instron 8501生物力学测试仪共同搭建实验平台,模拟生理状态下膝关节自站立位屈膝下蹲的动作。人工膝关节采用LPS全膝系统,手术由同一位有经验的术者实施以控制实验误差,比较以胫骨结节内、中1/3交界为标志(胫骨结节对线技术)和以股骨假体位置(ROM对线技术)确定胫骨假体旋转的2种技术所获得的髌股关节的生物力学指标,选择30°、60°、90°、120°为实验的观察角度进行各组实验,应用日本富士公司生产的超低敏感型压敏片、低敏感型压敏片测定髌股关节的接触面积和接触压,最后用FPD-305E、FPD-306E压力测定仪和电脑软件处理后得到数字化结果。[结果]人工膝关节置换术中胫骨结节对线技术组与ROM对线技术组所获得的髌股关节的平均峰值接触压、平均接触面积等指标无统计学差异(P>0.10)。[结论]全膝置换术中股骨假体参照经股骨上髁轴确定旋转方位后,采用胫骨结节对线技术抑或ROM对线技术来确定胫骨假体的旋转对线对髌股关节的生物力学未见显著差异。对于旋转限制性较高的假体,ROM技术能够在正确的胫股旋转对线和良好的髌骨轨迹之间作出平衡。

[ Objective] To study the biomechanical effect of two different rotational alignment techniques of the tibial component on patello-femoral in total knee arthroplasty demonstrated on autopsy specimens. [ Method] Nine fresh frozen autopsy knee specimens without gross deformities or instabilities were mounted on a patello-femoral joint testing jig connecting to a Model 8501 Instron machine （Instron Corporation, Canton, MA） and simulated the action of squatting from the standing opposition. Standard TKA was performed in each specimen by the same senior surgeon by using the LPS total knee systems （ Zimmer Corporation）. Alter rotational alignment of the tibial component was referred on the medial-middle 1/3 part of the tibia] tuberosity and on the rotational alignment of the femoral component which was determined by the transepicondylar axis separately. The blomechanics of the patello-femoral joints was studied when the knee flexion pressure of 30, 60, 90, 120 were measured respectively by using Fuji pressure sensitive film. The digital values were obtained by the handheld pressure measurement systems （FPD-305E, FPD-306E） and special software. [ Result] There was no significant difference in patello-femoral biomechanics between the group referring on the tibial tuberosity and the group referring on the femoral component in total knee arthroplasty demonstrated on autopsy specimens （P 〉0. 10）. [ Conclusion] After determining the rotational alignment of the femoral component referring on the transepicondylar axis, there is no significant difference on the patello-femoral biomechanics, whether using the ROM technique or the tibial tuberosity technique to determine the rotational alignment of the tibial component in TKA. Especially for the high-restrictively rotational designed prosthesis, this technique could get the satisfactory results both on the tibial-femoral match and on the patello-femoral biomechanics.