A Musculoskeletal Model of the Hand and Wrist Capable of Simulating Functional Tasks

Abstract

ObjectiveThe purpose of this work was to develop an open-source musculoskeletal model of the hand and wrist and to evaluate its performance during simulations of functional tasks. MethodsThe musculoskeletal model was developed by adapting and expanding upon existing musculoskeletal models. An optimal control theory framework that combines forward-dynamics simulations with a simulated-annealing optimization was used to simulate maximum grip and pinch force. Active and passive hand opening were simulated to evaluate coordinated kinematic hand movements. ResultsThe models maximum grip force production matched experimental measures of grip force, force distribution amongst the digits, and displayed sensitivity to wrist flexion. Simulated lateral pinch strength fell within variability of in vivo palmar pinch strength data. Additionally, predicted activation for 7 of 8 muscles fell within variability of EMG data during palmar pinch. The active and passive hand opening simulations predicted reasonable activations and demonstrated passive motion mimicking tenodesis, respectively. ConclusionThis work advances simulation capabilities of hand and wrist models and provides a foundation for future work to build upon. SignificanceThis is the first open-source musculoskeletal model of the hand and wrist to be implemented during both functional kinetic and kinematic tasks. We provide a novel simulation framework to predict maximal grip and pinch force which can be used to evaluate how potential surgical and rehabilitation interventions influence these functional outcomes while requiring minimal experimental data.