Akasaki Yukio, Matsuda Shuichi, Shimoto Takeshi, Miura Hiromasa, Higaki Hidehiko, Iwamoto Yukihide
Department of Orthopaedic Surgery, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
J Arthroplasty. 2008 Aug;23(5):736-43. doi: 10.1016/j.arth.2007.05.023.
The present study evaluated the effects of extent of conformity of post-cam design on contact area and stress at post-cam mechanism using 4 different posterior-stabilized prostheses. TRAC and Alpina with full-conformed post-cams exhibited the largest contact area at 90 degrees and 120 degrees . PFC sigma RPF with partial conformed post-cam had the largest contact area at 150 degrees . Scorpio NRG with less conformed post-cam had smaller contact area than the others. Lifting of femoral component decreased contact area and increased contact stress of TRAC and Alpina. Recent modifications of post-cam design have increased contact area, contributing to lower contact stress. None of these prostheses exhibited constant low contact stress throughout flexion. Further modifications of post-cam mechanism are necessary to provide lower contact stress throughout deep knee flexion.
本研究使用4种不同的后稳定型假体，评估后凸轮设计的贴合程度对后凸轮机构接触面积和应力的影响。具有完全贴合后凸轮的TRAC和Alpina在90度和120度时接触面积最大。具有部分贴合后凸轮的PFC sigma RPF在150度时接触面积最大。后凸轮贴合程度较小的Scorpio NRG接触面积比其他假体小。股骨部件的抬起会减小TRAC和Alpina的接触面积并增加接触应力。后凸轮设计的近期改进增加了接触面积，有助于降低接触应力。这些假体在整个屈曲过程中均未表现出恒定的低接触应力。需要对后凸轮机构进行进一步改进，以在屈膝深度范围内提供更低的接触应力。
