Influence of Limb Alignment on Mediolateral Loading in Total Knee Replacement
Influence of Limb Alignment on Mediolateral Loading in Total Knee Replacement
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DOI：
10.2106/jbjs.k.00927
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发表时间：
2012-06-06
影响因子：
5.3
通讯作者：
Bergmann, Georg
中科院分区：
文献类型：
--
作者：
Halder, Andreas;Kutzner, Ines;Bergmann, Georg
背景资料：全膝关节置换术后的对线不良可能会导致植入物轴承以及骨本身的过载，导致骨质溶解和早期松动。为了量化植入物必须承受的应力并定义肢体对线的安全区，必须确定总接触力及其内外侧分布。分析步态数据和数学模型已用于此目的。我们进行了这项研究，以确定在体内负荷的五名患者植入后的仪器胫骨baselite.Methods：5例膝关节骨关节炎接受全膝关节置换术。在胫骨部件上安装应变计，测量三个力和三个力矩。来自压力计的信号通过遥测传输到外部接收器。术后12个月，患者以自选的舒适速度步行通过水平人行道，获得术后测量结果。峰值轴向和内侧力的15至20个步态周期的平均值，并报告为个人体重的百分比。结果：在步态周期的立场相，两个最大的轴向力发生。典型值为第一峰时体重的215%，第二峰时体重的266%。在第一个轴向力峰值时，内侧载荷分担率通常为73%，在第二个轴向力峰值时为65%。个体间变异的分析显示与肢体排列呈线性相关。结论：与以往的研究结果一致，内侧间室传递的力通常大于外侧间室传递的力。关于全膝关节置换术的设计，具有较大内侧接触面积的不对称胫骨部件可能会降低骨上的峰值接触应力，并改善植入物的固定。对内外侧负荷分布进行量化，并与肢体对线相关，从而估计全膝关节置换术后对线不良的影响。
Background: Malalignment after total knee replacement could cause overloading of the implant bearing as well as of the bone itself, leading to osteolysis and early loosening. To quantify the stresses the implant has to withstand and to define a safe zone of limb alignment, the total contact forces as well as their mediolateral distribution have to be determined. Analytical gait data and mathematical models have been used for this purpose. We performed this study to determine in vivo loads of five patients after implantation of an instrumented tibial baseplate.Methods: Five patients with osteoarthritis of the knee received total knee replacement. The tibial component was instrumented with strain gauges for the measurement of three forces and three moments. The signals from the gauges were transferred telemetrically to an external receiver. At twelve months after surgery, postoperative measurements were obtained with the patients walking at a self-selected comfortable speed across a level walkway. Peak axial and medial forces of fifteen to twenty gait cycles were averaged and reported as a percent of individual body weight.Results: During the stance phase of the gait cycle, two maxima of the axial force occurred. Typical values were 215% of body weight at the first peak and 266% of body weight at the second peak. The medial load share was typically 73% at the first axial force peak and 65% at the second axial force peak. Analysis of inter-individual variations revealed a linear correlation with limb alignment. A deviation of 1 degrees varus from neutral alignment increased the medial load share by 5%.Conclusions: Consistent with the results of previous studies, we found that the force transferred by the medial compartment was usually greater than that transferred by the lateral compartment. Concerning the design of total knee replacements, an asymmetric tibial component with a larger medial contact area could possibly reduce peak contact stress on the bone and improve fixation of the implant. Mediolateral load distribution was quantified and correlated with limb alignment, thereby permitting the effects of malalignment after total knee replacement to be estimated.