An Automatically Adjusting Prosthetic Socket for People With Transtibial Amputation

Not Applicable

Recruiting

Conditions: Lower Limb Amputation Below Knee (Injury)
Diurnal Residual Limb Fluid Volume Fluctuation

Brief Summary: 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.

Recruitment & Eligibility

Inclusion Criteria

18 or older (Prosthetists and Prosthesis Users)
must have certification and regularly treat patients with trans-tibial limb loss in a clinical setting (Prosthetists only)
had a trans-tibial amputation at least 12 months prior (prosthesis users only)
regularly use a definitive prosthesis with pin lock suspension and few or no pads (prosthesis users only)
self-report experiencing limb volume fluctuation in the past (prosthesis users only)
have residual limb length of at least 9 cm (prosthesis users, Aim 2 and Aim 3 only)
walk at least 5 continuous minutes and intermittently at least 1 hour (prosthesis users, Aim 2 and Aim 3 only)
capable of distinguishing socket sizes too large and too small to be tolerated (Prosthetists and Prosthesis Users)

Exclusion Criteria

Are not certified prosthetists (prosthetists only)
neuropathy (prosthesis users only)
reduced skin sensation (prosthesis users only)
regular use of an assisted device (prosthesis users only)
sores or skin breakdown on their residual limb (prosthesis users, Aim 2 and Aim 3 only)

Arm && Interventions

Group	Intervention	Description
In-Lab, Crossover Study	Auto Adjusting Prosthesis	Testing of auto-adjusting algorithm in-lab. Participants will carry out a structured protocol wearing the socket in all modes. Order will be randomly assigned.
Out-of-Lab Crossover Study	Auto Adjusting Prosthesis	Evaluate socket performance in user free-living environments. Participants will use the prosthesis in all modes by end of study, order will be randomly assigned.

Primary Outcome Measures

Name	Time	Method
Integral Absolute Error of Control System	through study completion, an average of 1 year	Calculated error will be measured through each test session, both in and out of lab.
Socket Comfort Score	through study completion, an average of 1 year	Participants in Aim 2 and Aim 3 will test various configurations of the auto adjustment algorithm. Socket comfort score will be asked at various time points during testing, and overall changes in this metric will be calculated from the start and end of session.

Secondary Outcome Measures

Name	Time	Method
Percent change in Limb Fluid Volume	through study completion, an average of 1 year	Participant's limb fluid volume will be measured during the structured in-lab protocol (Aim 2), and changes will be compared against an initial reference point of activity during which no interventions will take place.
Thermal Recovery Time (TRT)	through study completion, an average of 1 year	An infrared (IR) camera will measure residual limb thermal recovery time at the beginning and end of testing--following at least 5 minutes of walking.

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