Design and experimental validation of an optimized wrist powered 3D printed mechanical transmetacarpal prosthesis

Abstract

In general, currently available 3D printed transmetacarpal prostheses in the market are being rejected by amputees due to their lower efficiency caused by the higher flexion angle and discomfort. One of the abundantly used process in fabricating prosthesis is by additive manufacturing technique due to its customizability and low cost. This study focuses on developing a novel 3D printed solution for transmetacarpal amputees. A modified version of the whippletree mechanismwasused to facilitate the adaptive grasp of the designed prosthesis that provides the ability to grasp objects of irregular shape. The whippletree mechanism plays an important role in force distribution to actuate all the fingers individually. To address the comfort issue, a cover made of flexible material covered with silicon adhesive was used at contact points. After fabricating and assembling the designed prosthesis, the performance of the design was analyzed by conducting several tests. The studies show that the new design has reduced the flexion angle nearly half in comparison with available design. This work concludesthat the novel3D printed transmetacarpal prosthesis provides improved function with minimal flexionangle and better comfort.