Quantification of third body damage to the tibial counterface in mobile bearing knees
Quantification of third body damage to the tibial counterface in mobile bearing knees
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DOI：
10.1243/0954411011533733
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发表时间：
2001-01-01
期刊：
影响因子：
1.8
通讯作者：
Fisher, J
中科院分区：
文献类型：
--
作者：
Jones, VC;Williams, IR;Fisher, J
分析了14对移位的低接触应力(LCS)胫骨界面假体：6个旋转平台(RP)、6个半月板(MN)和2个前后滑动(AP)设计，并特别注意了胫骨对应面的情况。胫骨托盘的平均表面粗糙度R-a在0.01um到0.087微米之间，显著大于未磨损的对照组测量的0.008微米。划痕几何分析表明，划痕峰的纵横比始终低于划痕谷，高度小于1微米(平均粗糙度高度R-p=0.52微米，纵横比DELTAP=0.01，平均粗糙度R-V=1.10微米)。Deltav=0.05)。R-P和R-V的最大划痕都是3-4微米。体外试验表明，超高分子量聚乙烯(UHMWPE)的磨损在存在垂直于运动方向的对面划痕时会增加。在这些外植体中，单向运动产生了平行于滑动方向的划痕，预计这会产生较小的UHMWPE磨损增加。其他设计的可移动轴承膝关节在胫骨对端面的运动约束较少，这已被证明加速磨损；这也可能导致第三身体划痕存在时磨损进一步增加。在未来的膝部设计中，有可能通过引入更耐刮擦和表面粗糙的替代材料或涂层来减少这种类型的磨损损害。
Fourteen pairs of explanted low contact stress (LCS) tibial interface components: six rotating platform (RP), six meniscal (MN) and two anterior-posterior (AP) glide designs, have been analysed with particular attention paid to the condition of the tibial counterfaces. The average surface roughness, R-a, for the tibial trays ranged from 0.01 to 0.087 mum, significantly greater than the unworn control measurement of 0.008 mum. The scratch geometry analysis showed that the scratch peaks were found to be consistently of a lower aspect ratio than the scratch valleys and under 1 mum in height (average asperity height R-p = 0.52 mum, aspect ratio Deltap = 0.01, average asperity depth R-v = 1.10 mum. Deltav = 0.05). The largest scratches were 3-4 mum in both R-p and R-v.In vitro tests have shown that ultra-high molecular weight polyethylene (UHMWPE) wear increases in the presence of counterface scratches perpendicular to the direction of motion. In these explants, the unidirectional motion produced scratches parallel to the direction of sliding which is predicted to produce a smaller increase in UHMWPE wear. Other designs in mobile bearing knees have less constrained motion at the tibial counterface and this has been shown to accelerate wear; it may also lead to a further increase in wear in the presence of third body scratches. It may be possible in future knee designs to reduce this type of wear damage by introducing alternative materials or coatings which are more resistant to scratching and surface roughening.