Hull Maury L
Department of Biomedical Engineering, University of California Davis, Davis, CA 95616, United States; Department of Mechanical Engineering, University of California Davis, Davis, CA 95616, United States; Department of Orthopaedic Surgery, University of California Davis Medical Center, Sacramento, CA 95817, United States.
J Biomech. 2020 Aug 26;109:109928. doi: 10.1016/j.jbiomech.2020.109928. Epub 2020 Jul 2.
The relative rigid body motions between the femur and the tibia (termed tibiofemoral kinematics) during flexion activities can provide an objective measure of knee function. Clinically meaningful tibiofemoral kinematics are defined as the six relative rigid body motions expressed in a joint coordinate system where the motions about and along the axes conform to clinical definitions and are free from kinematic crosstalk errors. To obtain clinically meaningful tibiofemoral kinematics, coordinate systems must meet certain requirements which neither have been explicitly stated nor in fact satisfied in any previous publication known to the author. Starting with the joint coordinate system of Grood and Suntay (1983) where motions conform to clinical definitions, the body-fixed axes must correspond to the functional (i.e. actual) axes in flexion-extension and internal-external axial rotation to avoid kinematic crosstalk errors in rotations and both functional axes must be body-fixed throughout knee flexion. To avoid kinematic crosstalk errors in translations, the origins of the femoral and tibial Cartesian coordinate systems, which serve as stepping stones for computing translations, must lie on the functional body-fixed axes. Neither the paper by Grood and Suntay nor the ISB recommendation (Wu et al., 2002) which adopted the joint coordinate system of Grood and Suntay explains these requirements. Indeed meeting these requirements conflicts with the ISB recommendation thus indicating the need for revision to this recommendation. Future studies where clinically meaningful tibiofemoral kinematics are of interest should be guided by the requirements described herein.
在膝关节屈曲活动过程中，股骨和胫骨之间的相对刚体运动（称为胫股运动学）能够为膝关节功能提供客观的测量指标。具有临床意义的胫股运动学被定义为在关节坐标系中表达的六种相对刚体运动，其中围绕轴和沿轴的运动符合临床定义，并且不存在运动学串扰误差。为了获得具有临床意义的胫股运动学，坐标系必须满足某些要求，而这些要求在作者所知的任何先前出版物中既未明确说明，实际上也未得到满足。从Grood和Suntay（1983年）的关节坐标系开始，其中运动符合临床定义，在屈伸和内外轴向旋转中，身体固定轴必须与功能（即实际）轴相对应，以避免旋转中的运动学串扰误差，并且在整个膝关节屈曲过程中，两个功能轴都必须固定在身体上。为了避免平移中的运动学串扰误差，作为计算平移的基础的股骨和胫骨笛卡尔坐标系的原点必须位于功能身体固定轴上。Grood和Suntay的论文以及采用Grood和Suntay关节坐标系的国际生物力学学会（ISB）建议（Wu等人，2002年）都没有解释这些要求。实际上，满足这些要求与ISB建议相冲突，因此表明需要对该建议进行修订。未来对具有临床意义的胫股运动学感兴趣的研究应以本文所述的要求为指导。
