背景:开发了保留双关节的全膝关节置换术(BCR-TKA)以维持前交叉韧带功能,从而在术后再现自然的膝关节运动学。传统手术技术,然而,可能会导致一些并发症继发于运动学冲突和韧带过度紧张。这项研究的目的是使用对称BCR-TKA的计算机模拟来评估替代手术技术对膝关节运动学和韧带的影响。
方法:构建了健康膝盖的肌肉骨骼计算机模型,并将其用于模拟具有机械对准(MA)的BCR模型。研究了五个调整后的模型,characterized,分别,通过运动学对准(KA),胫骨斜度增加2度,胫骨组件的远端两毫米,和带MA或KA的过小股骨组件。
结果:所有模型在膝关节伸展时对胫骨表现出正常的股骨位置,在中屈期间没有前反常运动。健康的膝盖模型显示内侧枢轴运动和回滚。相比之下,BCRMA模型显示双髁异常回滚,膝关节屈曲时外侧副韧带和后交叉韧带过度紧张,而带MA的过小股骨模型部分降低了两种张力。BCRKA模型保留了相对生理的运动学并抑制了过度的韧带张力。然而,没有调整后的模型完全再现健康的膝关节状况。
结论:由于保留的韧带和替换的关节表面之间的运动学冲突,BCRMA模型显示出异常的生物力学。使用对称BCR-TKA的外科医生应考虑使用KA方法在整个膝关节屈曲过程中实现足够的韧带松弛。
BACKGROUND: Bicruciate-retaining total knee arthroplasty (BCR-TKA) was developed to maintain anterior cruciate ligament function and thus reproduce natural knee kinematics postoperatively. Traditional surgical techniques, however, may cause several complications secondary to kinematic conflict and ligament overtension. The objective of this study was to use a computer simulation of symmetric BCR-TKA to evaluate the effects of alternative surgical techniques on knee kinematics and ligaments.
METHODS: A musculoskeletal computer model of a healthy knee was constructed and was used to simulate a BCR model with mechanical alignment (MA). Five adjusted models were investigated, characterized, respectively, by kinematic alignment (KA), two degrees increased tibial slope, two-millimeter distal setting of the tibial component, and an undersized femoral component with either MA or KA.
RESULTS: All models exhibited a normal femoral position against the tibia at knee extension, with no anterior paradoxical motion during mid-flexion. The healthy knee model showed medial pivot motion and rollback. In contrast, the BCR MA model demonstrated abnormal bi-condylar rollback with excessive tensions of the lateral collateral ligament and posterior cruciate ligament during knee flexion, whereas the undersized femoral model with MA partly reduced both tensions. The BCR KA model retained relatively physiological kinematics and suppressed excessive ligament tensions. However, no adjusted model completely reproduced healthy knee conditions.
CONCLUSIONS: The BCR MA model showed abnormal biomechanics due to kinematic conflict between the retained ligaments and the replaced joint surface. Surgeons using symmetric BCR-TKA should consider using the KA method to achieve sufficient ligament laxity throughout knee flexion.