Ipsilateral Scapular Cutaneous Anchor System: An alternative for the harness in body-powered upper-limb prostheses

BACKGROUND Body-powered prosthesis users frequently complain about the poor cosmesis and comfort of the traditional shoulder harness. The Ipsilateral Scapular Cutaneous Anchor System offers an alternative, but it remains unclear to what extent it affects the perception and control of cable operation forces compared to the traditional shoulder harness. OBJECTIVE To compare cable force perception and control with the figure-of-nine harness versus the Ipsilateral Scapular Cutaneous Anchor System and to investigate force perception and control at different force levels. STUDY DESIGN Experimental trial. METHODS Ten male able-bodied subjects completed a cable force reproduction task at four force levels in the range of 10-40 N using the figure-of-nine harness and the Anchor System. Perception and control of cable operating forces were quantified by the force reproduction error and the force variability. RESULTS In terms of force reproduction error and force variability, the subjects did not behave differently when using the two systems. The smallest force reproduction error and force variability were found at the smallest target force level of 10 N. CONCLUSION The Anchor System performs no differently than the traditional figure-of-nine harness in terms of force perception and control, making it a viable alternative. Furthermore, users perceive and control low operation forces better than high forces. Clinical relevance The Ipsilateral Scapular Cutaneous Anchor System offers an alternative for the traditional harness in terms of cable operation force perception and control and should therefore be considered for clinical use. Low cable operation forces increase the perception and control abilities of users.