Development of a clinically adoptable joint coordinate system for the wrist

Kinematics play a vital role in answering both clinical and research questions regarding joint biomechanics. Standardisation of kinematic approaches is important; however, the method that is currently recommended for building the joint coordinate system (JCS) to measure kinematics of the wrist is difficult to implement in vivo. In this study, a series of JCSs were examined and compared to the International Society of Biomechanics (ISB) recommendations in terms of landmark digitisation repeatability, coordinate frame creation repeatability, and secondary rotations during planar motion. No differences were found between the ISB JCS and 338 of 408 of the JCSs proposed in the study, meaning that the proposed alternative can be used without affecting the measured joint angles or repeatability of the JCS. Forearm frames that used a vector between the epicondyles to define the YZ plane of the forearm were found to create JCSs that produced secondary rotations greater than that which would be clinically detectable and thus, they should be avoided when defining a JCS. The remaining 338 coordinate systems can be used interchangeably; consequently, should there be any clinical limitations that result in missing landmarks, alternative coordinate systems can be used. A joint coordinate system created using the radial styloid, ulnar styloid, medial epicondyle, lateral epicondyle, the heads of the second and fifth metacarpal, and the base of the third metacarpal is recommended for quantifying kinematics in vivo.