A Test-Drive Strategy for the Prescription of Prosthetic Feet for People With Leg Amputations
Condition: Amputation
Study type: Interventional

Summary: 
      Objective/Hypotheses and Specific Aims: The primary aim of this proposal is to determine
      whether a PFE can be used to predict foot preference and mobility outcomes with corresponding
      commercial prosthetic feet in people with a unilateral transtibial amputation (TTA).
      Secondarily, the investigators aim to determine whether a brief trial of commercial
      prosthetic feet would be able to similarly predict longer-term foot preference and mobility
      outcomes with those feet.

      Study Design: The investigators will use a participant blinded cross-over study with repeated
      measurements. Participants with TTA will be enrolled at each of the three study sites: two VA
      sites (Puget Sound and Minneapolis), and one Department of Defense site (Center for the
      Intrepid). Participants will complete up to 6 visits. After an initial assessment visit,
      participants will be assigned to the high or low mobility group, and then during visit 2 they
      will be randomized to use the PFE in three foot modes or the three corresponding actual
      (commercially available) feet during walking tests in the laboratory. During visit 3
      participants will repeat the procedures in the other condition (e.g., PFE if Day 2 included
      actual feet testing). At the end of visit 3 participants will be fit with one of the actual
      feet and wear it at home and in the community for approximately two weeks. At visit 4
      participants will be fit with the next actual foot and repeat the 2 week use window. The same
      process will be followed for the final foot at visit 5, and the study foot will be returned
      at visit 6. Participants' preference, satisfaction and perceived mobility, and functional
      mobility will be measured and compared across all foot conditions (emulated and actual).
      After participants complete the procedures detailed above, they may be eligible to be invited
      to participate in follow-up phone interviews. A subset of participants may also be invited to
      participate in follow-up biomechanical data collection comparing the PFE foot conditions to
      the respective actual prosthetic feet during walking. Additionally, a subset of participants
      may also be invited to participate in follow-up data collection comparing prosthetic foot
      conditions of different stiffness categories.
    

Detailed description: 
      Objectives and Rationale: Using a prosthesis allows many who experience lower leg amputation
      to regain functional abilities, but walking may be more difficult, and a sub-optimal
      prosthesis can substantially restrict participation in desired activities. Selecting an
      optimal prosthetic foot is an important aspect of maximizing mobility and the achievement of
      functional goals for people with lower leg amputation, however there is limited evidence to
      guide this process. The current prosthetic prescription process relies on clinician
      experience and typically does not allow people with a leg amputation to easily try out
      different prosthetic feet. The investigators have developed a customizable robotic prosthetic
      foot that mimics the mechanical properties of commercially available prosthetic feet without
      physically changing feet. This 'prosthetic foot emulator' (PFE) can be attached to the
      prescribed prosthetic socket and worn like a regular prosthetic foot within the laboratory or
      clinic, providing people with leg amputations the opportunity to quickly 'test-drive' many
      prosthetic foot designs within a single test session. Trial and error with actual commercial
      prosthetic feet can be inefficient given the time and expense required for the purchasing and
      fitting of prosthetic feet. The PFE could provide a means to explore a range of feet in a
      very short period of time. This study will evaluate the ability of the emulator to accurately
      reproduce the experience of wearing several commercially available (actual) prosthetic feet.
      The investigators will test whether brief in-laboratory experiences with emulated or actual
      feet can accurately predict longer-term foot preference, satisfaction, and walking ability in
      the community. The investigators will also evaluate the experiences of prosthetic foot
      prescription practices using qualitative methods from follow-up phone interviews with
      participants. Finally, the investigators will evaluate biomechanical outcomes during walking
      between the PFE and actual prosthetic feet to examine the ability of the emulator to
      accurately reproduce the experience of walking with the actual feet. Results from this study
      may provide evidence to support a new approach to prosthesis prescription and could resolve
      longstanding uncertainty in the prescription process for prosthetic feet.
    

Intervention name(s): Prosthetic Foot Emulator; Commercially available prosthetic feet
Intervention type(s): Device; Device
Intervention description(s): Participants will walk in the laboratory with the Prosthetic Foot Emulator (PFE) in three foot modes corresponding to actual study feet. Walking conditions will include self-selected speed, slow speed, fast speed, incline, and up stairs.; Participants will walk in the laboratory with three different commercially available prosthetic feet. Walking conditions will include self-selected speed, slow speed, fast speed, incline, and up stairs.
Additionally, participants will be fit with one of the actual feet and wear it at home and in the community for approximately two weeks. This will be followed by two-week periods in the community with each of the other two commercially available prosthetic feet.
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Single (Participant)
Primary purpose: Treatment
Keywords: Amputation; Rehabilitation; Prescriptions; Emulator; Prosthetics