A common problem for the intermediate preparatory stage of prosthetic rehabilitation is distal pressure, due to commonly compromised sensation and lack of understanding how to address it in a newly fitted prosthesis. Excessive pressure can lead to severe skin breakdown, infection, surgical revision, re-hospitalization and delayed rehab. To prevent this common problem among rehabilitating amputees, smart socket technology has been developed to better identify problems that may occur. The Smart Socket Technology including Prompting (SST+P) in this pre-clinical project proposal provides a step activity monitor and senses distal pressure, which is novel to the technology. When excessive pressure is sensed on the residual limb, it will send a signal to the user's smart phone to make an adjustment. This prompting improves patient interaction and may prevent problems as a result of common volume fluctuation and compromised sensation. The purpose of this clinical trial is to determine if the ALPS iForce smart socket technology with prompting (SST+P) will improve patient interaction, usability, comfort, fit, function and health economy outcomes compared with the standard of care (SOC) clinical practice protocols of fitting prosthetic socket interfaces

Limb loss requires prosthetic use. Prostheses usually consist of 2 components: 1) a soft interface to protect the skin and underlying musculoskeletal tissue and 2) a structural interface to enable attachment of prosthetic components to the human body. The interface connects the patient's body to the prosthetic components and thus ground during gait. The interface has 2 purposes: 1) to distribute weight-bearing forces throughout the entire residual limb (RL) and 2) to suspend the prosthesis during swing phase and unweighting. The interface assists in distributing vertical loads during weight bearing to minimize focal loading on pressure intolerant tissues. The interface also suspends prosthetic components to the RL in swing phase and other periods of unweighting.

Many amputees experience RL complications and decreased mobility resulting from the inability to detect excess pressure or a lack of distal contact with newly fit and poorly fit interfaces. A smart socket technology interface could benefit every new prosthetic patient by prompting the user of a compromised socket fit prior to inhibiting functional use and safety. Further, the smart socket technology interface may ultimately prevent other health complications and improve patient interaction, usability, comfort, fit and function. The ALPS iForce most economically measures these variables more comprehensively than any other known single device. Therefore the smart socket interface technology chosen for this proposal is the ALPs iForce. The iForce tracks pressure over time and indicates to the user when positive or negative distal pressure exists by providing volume management suggestions (i.e. sock-ply adjustments). The user interacts with data measured sent wirelessly to an application on a smart phone (Android/iOS/Windows), handheld device, or PC. Suggestions may include removal or application of prosthetic socks over the RL, or other appropriate volume management strategies, to improve fit and comfort. Early warning to possible skin irritation and breakdown may lead to a healthier limb.

Inclusion Criteria:

1. Unilateral transtibial amputation
2. Unilateral revision or reconstruction of transtibial amputation
3. Candidate for intermediate stage (i.e. preparatory) socket fitting
4. Male or female, of any ethnicity
5. 18-60 yrs of age (i.e. active military age)
6. 100-275 lbs.

Exclusion Criteria:

1. Body weight <100 or >275 lbs
2. Does not speak English or Spanish
3. Any other level of amputation than unilateral TTA