Minoda Yukihide, Ikebuchi Mitsuhiko, Mizokawa Shigekazu, Ohta Yoichi, Nakamura Hiroaki
Department of Orthopaedic Surgery, Osaka City University Graduate School of Medicine, Osaka, Japan.
J Knee Surg. 2018 May;31(5):416-421. doi: 10.1055/s-0037-1604143. Epub 2017 Jul 12.
Malrotation of tibial components is one of the important causes of failure in total knee arthroplasty. The aim of this study is to determine the relationship between tibial rotational positioning and coverage of the tibial surface during the operation, using a symmetric and newly introduced asymmetric medial pivot tibial components. The coverage and overhang were compared between a symmetric component (Advance medial pivot) and a newly introduced asymmetric medial pivot tibial component (Evolution medial pivot) in 31 knees during the operation. When the tibial component was placed parallel to the anteroposterior (AP) axis, the uncovered width in the posteromedial part using a symmetric design was larger than that using an asymmetric design ( < 0.01). Overhang in the posterolateral part was observed in 42% for a symmetric design and 3% for an asymmetric design ( < 0.01). When the component was placed in malrotation (10 degrees internal to the AP axis), overhang in the posteromedial part was observed in 6% for a symmetric design and in 71% for an asymmetric design ( < 0.01). The tibial rotation parallel to the AP axis and maximizing coverage of the tibial surface conflict in a symmetric design, but are compatible in an asymmetric design. An asymmetric tibial component is expected to improve the coverage and the rotational positioning of medial pivot total knee prosthesis.
胫骨部件旋转不良是全膝关节置换术失败的重要原因之一。本研究的目的是使用对称的和新推出的非对称内侧旋转平台胫骨部件，确定手术过程中胫骨旋转定位与胫骨表面覆盖情况之间的关系。在手术过程中，对31例膝关节的对称部件（Advance内侧旋转平台）和新推出的非对称内侧旋转平台胫骨部件（Evolution内侧旋转平台）的覆盖情况和悬垂情况进行了比较。当胫骨部件与前后（AP）轴平行放置时，使用对称设计时后内侧部分的未覆盖宽度大于使用非对称设计时的未覆盖宽度（<0.01）。对称设计中42%的膝关节出现后外侧悬垂，非对称设计中为3%（<0.01）。当部件处于旋转不良状态（相对于AP轴内旋10度）时，对称设计中6%的膝关节出现后内侧悬垂，非对称设计中为71%（<0.01）。在对称设计中，与AP轴平行的胫骨旋转和最大化胫骨表面覆盖情况相互矛盾，但在非对称设计中两者是兼容的。预计非对称胫骨部件可改善内侧旋转平台全膝关节假体的覆盖情况和旋转定位。
