Utility of Body-Powered Voluntary Opening and Closing Terminal Devices on Transradial Prostheses

An upper arm prosthesis should restore the ability to feed oneself, lift or carry objects, dexterously pick up and manipulate objects in one’s environment, drive a vehicle, and tie one’s shoes. Individuals with limb amputation are often fitted with a body-powered terminal device that either opens or closes upon activation by the user and is termed a voluntary opening or voluntary closing device. This mixed-methods study compared the outcomes of both body-powered terminal devices using a holistic approach. Eight participants with an amputation and ten able-bodied participants’ performances and preferences were evaluated using both the Hosmer model 5XA VO hook and the TRS 30 VC terminal devices. Participants performed unilateral and bilateral lifts, the Box and Block Test, the Continuous Scale-Physical Functional Performance-10 Test, open-ended qualitative feedback, and the Trinity Amputation and Prosthesis Experience Scales – Revised. Two-tailed data analysis included t-tests with Bonferroni post hoc adjustments, Fischer Exact Test, Mann-Whitney U, and qualitative evaluation. Participants with an amputation statistically preferred the voluntary opening device’s aesthetics and usability. Data concerning lifts, the Box and Block Test, the Continuous Scale-Physical Functional Performance-10 Test showed no statistical differences. This data supports previous studies. Those involved in selecting and fitting upper arm prostheses must understand each patient’s goals and priorities to select the best terminal device for the patient. Ideally, an individual with an upper extremity amputation can choose between VO and VC terminal devices to select the right tool for the required task.