A Biomechanical Comparison of Carpometacarpal Joint Bridging and Sparing Wrist Fusion Plates

Abstract Total wrist fusion is a commonly used surgical treatment for wrist arthritis. When performing this surgery there is limited clinical evidence for whether to bridge or spare the third carpometacarpal (CMC) joint to guide surgeons when fusing the carpal bones of the wrist. The aim of this study is to compare the stiffness of CMC sparing and CMC bridging plates biomechanically. The stiffness of six sparing CMC wrist fusion plates and six bridging CMC fusion plates were compared biomechanically. This was performed with the plates mounted on 3D-printed models to replicate the wrist, using materials testing machine. There was no significant difference in stiffness between the CMC sparing and CMC bridging plate. Based on this study we cannot recommend one fusion plate over the other. While further cadaveric biomechanical testing may yield more information, based on this study we advise surgeons to choose the plate they feel provides satisfactory outcome.