The proposed research addresses the FY17 PRORP Rehabilitation Focus Area, Prosthetic and/or Orthotic Device Function. Service members using prostheses often experience socket fit problems resulting from a change in the volumes of their residual limbs. Volume losses as low as 1% can cause a clinically detectable change in socket fit. While intermittently doffing their prostheses has been shown to increase limb fluid volumes back to normal, most prosthesis users ignore the need and put up with ill-fitting sockets because of the inconvenience of removing and re-donning a socket. However, ill-fitting sockets can reduce performance and lead to injury.

The primary objective of this research is to develop and test electronic “release and relock” socket systems for trans-tibial prosthesis users. These systems allow users to quickly loosen their socket and partially withdraw their residual limbs without losing contact with their prostheses. After fluid volume recovery, the system allows users to re-don and lock their sockets within seconds, minimizing distraction and allowing a quick return to action. Recovered fluid volume is maintained during subsequent activity, and users are more functional because their prosthetic fit is improved. The developed system is an improvement over current volume management techniques because it does not reduce socket size, and thus does not accentuate limb volume loss. It operates quickly, allows users to make adjustments through their clothing using one hand, and ensures that users never lose contact with their prostheses. In this research, performance of release and relock sockets is tested in laboratory studies. Long-term field studies are conducted to determine whether use of release and relock sockets enhances patient outcomes relative to traditional sockets.

A secondary objective of this research is to test new outcome assessment tools used in the clinical testing. The release and relock sockets are instrumented to measure novel outcomes data of interest to practitioners. We will show practitioners of willing study participants the clinical outcomes data summaries and conduct qualitative interviews to assess the clinical value and technical quality of the collected information.

The developed technology will help patients with amputation who experience limb volume fluctuations using their prostheses. This includes active Service members and Veterans who are distracted from their duties and reduce their performance because of poorly fitting prosthetic sockets. Seventeen percent of Service members from Vietnam and 13% from Operation Iraqi Freedom/Operation Enduring Freedom cannot routinely wear their prostheses because of poorly fitting sockets. Individuals who experience limb pain or injury because they do not make needed adjustments when they should will also benefit. The developed technology should improve the productivity and well-being of people with limb loss.