Powered humeral rotator for persons with shoulder disarticulation amputations

Abstract: There are no commercially available externally-powered humeral rotators. This paper describes the development of a new powered-humeral rotator based on an LTI Boston Elbow II drive train suitable for use on persons with short transhumeral amputations or shoulder disarticulation amputations. An initial fitting of the device as part of a six motor arm demonstrated the efficacy of the device and anecdotal evidence suggested the patient found the device to be of benefit. Introduction: It is estimated that out of a total of about 100,000 upper-limb amputees in the USA that about 18 % have trans-humeral amputations or higher [Laplante & Carlson, 1997; Millstein et al., 1985; 1986]. For the upper arm the normal range-of-motion for humeral rotation is 90 ° of medial (inward-towards the midline) humeral rotation and 40 ° of lateral (outward-away from the midline) humeral rotation. However, persons with high-level arm amputations (trans