People with leg amputations often experience daily changes in the size (volume) of their residual limb. These daily changes can cause a prosthesis to fit poorly. They can also cause limb problems like pain or skin breakdown. Prosthetic socket systems that accommodate limb volume changes can help address these issues, but they require users to make adjustments throughout the day. The aim of this research is to create a system that will automatically adjust the fit of the socket and create a well-fitting prosthesis for people with leg amputations who experience volume fluctuations when using their prosthesis.

he goal of this research is to determine if an automatic-adjusting prosthetic socket produces better participant outcomes than a manually-adjusting socket or a standard of care control in people with trans-tibial limb amputation. Prosthesis users will wear each socket configuration for 2 weeks. Endpoints will include self-reported comfort, convenience, and fatigue; residual limb health; wear time; activities time; and variability in socket fit. Each condition will be tested separately in a cross-over study design, including a 2-week washout period between the conditions. This aim will use a crossover randomized trial to evaluate the importance of the socket condition The three test conditions will be (1) an automatic-adjusting socket; and (2) a manual-adjusting socket; and (3) a standard of care (adjust socks) control in which socket adjustment is locked. Participants will test each of these three conditions in a random order. There will be a 2-week washout period between test conditions. Participation will begin with an initial sessions where the researchers will evaluate inclusion criteria, collect demographic information, conduct a brief bioimpedance test and thermal imaging test, scan the participant's existing socket and instrument the participant's traditional socket with a monitor to collect activity data for 2 weeks while the investigational prosthesis is fabricated. When the investigational prosthesis is prepared, participants will return to the lab. Self-report questionnaires will be completed, and residual limb health assessed. The participant will be trained on how to operate the socket. The socket will be set to the first condition (order of conditions randomly selected). After using the socket for 3 to 5 days, the researchers will go to the participant's location for a check-in visit. The participant will have an opportunity to ask questions and discuss any issues they are having with the socket. The researchers will make sure the socket is functioning properly. After 2 weeks total, participants will return to the lab and complete self-report questionnaires and have their residual limb health assessed. They will participate in an interview about their experience wearing the socket. After a 2-week washout period, they will conduct the same procedure wearing another socket condition. After another 2-week washout period, they will conduct the same procedure wearing the remaining socket condition.

• 18 years or older
• Unilateral or bilateral trans-tibial amputation at least 12 months prior
• Have a limb of length 9 cm or greater
• Are capable of at least 5 minutes of continuous walking
• Are capable of at least 1 hour of intermittent walking
• Regularly use a definitive prosthesis with a pin-lock suspension system and no or few pads
• Have adequate sensation to verbalize a socket that is too large or too small to be tolerated
• Do not regularly use assistive devices (e.g., cane, walker) for ambulation
• Do not have open wounds on their residual limb at the time of enrollment