Todo Shinichi, Blunn Gordon W, Harrison Mark, Freeman Michael A R
Yasaka-cho Kokuho Hospital, Kyoto, Japan.
Biomed Mater Eng. 2003;13(3):231-4.
Femoral lift-off has been reported in total knee arthroplasty using dynamic fluoroscopic analysis. However, the effect of femoral lift-off on ultra-high-molecular-weight polyethylene (UHMWPE) is not clear. The objective of this study was to evaluate the effect of lift-off movement on the wear of UHMWPE using a pin-on-disc testing machine. Using oxidised UHMWPE, delamination was observed in 70% of the discs with lift-off movement, as against none in without lift-off movement (p=0.0603). In non-oxidised UHMWPE the depth of the wear track was increased in the impact area after lift-off, but there was no delamination and no increase in wear as measured by weight loss. UHMWPE can sustain the impact of after lift-off with neither delamination nor wear by other mechanisms. In contrast, degraded (i.e., oxidised) UHMWPE undergoes delamination after lift-off. Since it is probable that lift-off cannot be prevented, oxidised UHMWPE should never be used in TKA.
在全膝关节置换术中，通过动态荧光透视分析已报告了股骨抬起现象。然而，股骨抬起对超高分子量聚乙烯（UHMWPE）的影响尚不清楚。本研究的目的是使用销盘试验机评估抬起运动对UHMWPE磨损的影响。使用氧化的UHMWPE时，70%有抬起运动的圆盘出现分层，而无抬起运动的圆盘未出现分层（p = 0.0603）。在未氧化的UHMWPE中，抬起后冲击区域的磨损轨迹深度增加，但未出现分层，且通过重量损失测量的磨损也未增加。UHMWPE能够承受抬起后的冲击，既不分层也无其他机制导致的磨损。相比之下，降解（即氧化）的UHMWPE在抬起后会发生分层。由于很可能无法防止抬起现象，氧化的UHMWPE绝不应在全膝关节置换术中使用。
