Muscle Forces and Articular Loading Following In Vitro Total Wrist Arthroplasty

Total wrist arthroplasty (TWA) is a surgical option for individuals with end-stage wrist arthritis; however, their longevity remains below that of the hip and the knee. The objective of this study was to examine the muscle forces and articular loading patterns following TWA to better understand possible failure modes. Eight cadaveric specimens underwent active motion simulation representing planar flexion-extension and planar radial/ulnar deviation in both intact and TWA reconstructed states using a custom load sensing TWA. Results showed that muscle forces for extensors increased post-TWA implantation when extending the joint, whereas the flexors remain relatively unchanged. In addition, the articular loading was greater during extension than during flexion and during ulnar deviation than during radial deviation. The increase in muscle forces and high carpal component loading postimplantation may contribute to decreased longevity and early failure of implants.