Prosthetic Systems at Prosthetic & Orthotic Associates
Hip Disarticulate/Hemipelvectomy/ Transpelvectomy NPS (vacuum) Prosthetic System
POA’s patented NPS socket system for hip disarticulate amputations was created by Stan Patterson for Sgt. Josh Olson (photo at right) at the request of Walter Reed Army Medical Center (WRAMC). Olson, who lost his leg as the result of an RPG blast in Iraq, wanted to remain in the Army, but the hip disarticulate prosthetic system he was wearing was rigid, bulky, and so uncomfortable that he found it hard to function in. So in 2004, WRAMC sent Josh to POA to create something that would serve him better. Fourteen-hour days and several prototypes produced a low-profile model that was not visible through Olson’s uniform. A custom silicone liner created an effect like a suction cup in a socket that was half the size of previous models. The fit is intimate and secure, preventing the socket movement that beset old versions. Improvements to the liner and socket interface have evolved since then, but the initial design, named the “Olson socket,” is basically the same.
Overview: Prosthetic Fitting Process for HD/HP/TP Amputees
After a patient is fit with a custom-made medical grade silicone liner (fabricated on-site in our lab) the socket is designed and formed over it, providing a precise and comfortable fit. A light-weight carbon fiber disc containing Negative Pressure Suspension (NPS) technology is inserted into a pocket formed into the silicone liner. Additional components are added and the resulting prosthesis provides the highest degree of control possible, allowing the wearer to walk with confidence–and sit in comfort!