While custom sockets for prosthetic legs may sound like a great thing, they don’t conform to the changing shape of an amputee’s stump. That’s because live tissue can gain or lose interstitial compartment fluid volume throughout the day, turning any fit that worked in the morning into an uncomfortable experience by the end of the day. Moreover, the stump is soft and doesn’t have the durability of soles of feet that were designed to bear the load of a full size human. To help overcome these issues and offer all-day comfort, researchers at Sandia National Labs, a subsidiary of Lockheed Martin, have developed a special sensor and shape changing socket to regularly adjust the fit.
The sensor detects pressure within the socket being applied to it in multiple directions: perpendicular to and along the length of the leg. This is important because the sheer forces applied along the leg rub and pull on the skin, often creating substantial pain that cause many amputees to stop using their prostheses. The socket they developed has built-in pockets that can be filled with a fluid to change its shape based on the sensor readings. So far the technology is still in a fairly early developmental stage, as the researchers need to learn how to adjust the socket to the sensor readings to provide all-day comfort.
Here’s a video report from Sandia presenting the new prosthetic technology: