Shoulder region socket considerations

Amputations or congenital deficiencies in proximity to the glenohumeral joint traditionally have limited functional success and have a high rate of rejection. Many of the critical factors that have led to the high rejection rates are directly related to the design of the prosthetic socket. A good understanding of the factors that lead to rejection can be used to optimize the socket. Factors such as primary and secondary controls combine with biomechanical requirements to establish the unique requirements for each prosthetic system. There is not one socket design that works for all control types and functional applications. Socket designs that address the combination of biomechanical principles with the requirements of the control system employed will best serve the needs of the user. Case studies are presented to illustrate such a combined approach. Deficiency levels represented through the case reports are short transhumeral with brachial plexus and fused glenohumeral joint, humeral neck, shoulder disarticulation, interscapular thoracic and bilateral prosthetic users. Case studies illustrate various control methods including; myoelectric, cable-operated, body-motion operated electric (force sensor and force sensing resistor), activity specific, hybrid, and bilateral glenohumeral region fittings. A case study is also presented on the emerging technology of targeted muscle reinnervation.