Objective/Hypotheses and Specific Aims: The first aim of this proposal is to determine the effects of commercial prosthetic feet of varying stiffness on stability and falls-related outcomes in Veterans with TTA. The second aim is to determine whether a PFE can be used to predict stability and balance-confidence outcomes with corresponding commercial prosthetic feet. The third and final aim is to determine whether a brief trial of commercial prosthetic feet can predict longer-term stability and balance-confidence outcomes in Veterans with TTA.
Study Design: The investigators will use a participant blinded cross-over study with repeated measurements in Veterans and Service members with TTA. Up to 50 participants will be enrolled at each of the two study sites VA Puget Sound and VA Minneapolis. 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 on difference surfaces in the laboratory (cross-slopes, inclines, even, and uneven ground). During visit 3 participants will repeat the procedures in the other condition (e.g., PFE if visit 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 one week. At visit 4 participants will be fit with the next actual foot and repeat the 1 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.
has a unilateral (one leg) transtibial (below-knee) amputation
has used a prosthetic limb for walking for at least six months
has a comfortably fitting prosthetic socket
has a removable prosthetic foot attachment (i.e., is not rigidly attached to the back of the socket) so it can be used with study prosthetic feet
contralateral limb or upper limb amputation that would interfere with completion of study activities
are unable to use more than one of the test feet for any reason (e.g., excessively long residual limb that is not compatible with wearing study prosthetic feet)
unable to walk under the minimal necessary study walking conditions in order to complete the study procedures without undo stress
current surgical, neurological, rheumatologic, or lower limb musculoskeletal problem that significantly impairs ambulation (e.g., current ulcer, terminal illness)
Crossover
Multiaxial Prosthetic Foot Emulator
DeviceParticipants will walk in the laboratory with the multiaxial Prosthetic Foot Emulator (PFE) in three foot modes corresponding to commercial prosthetic study feet. Walking conditions will include self-selected comfortable, slow, and fast speeds, inclines, cross slopes, and uneven terrain.
Commercially available prosthetic feet
DeviceParticipants will walk in the laboratory with the commercial prosthetic study feet in three foot modes corresponding to commercial prosthetic study feet. Walking conditions will include self-selected comfortable, slow, and fast speeds, inclines, cross slopes, and uneven terrain. Additionally, participants will be fit with one of the commercial prosthetic study feet and wear it at home and in the community for approximately one week. Participants will return to the laboratory to follow-up testing, and will complete the community trial with each of the three commercial prosthetic study feet.
Self-report: perceived stability
Correlation between prosthetic foot sagittal and coronal plane stiffness properties and perceived stability during walking on uneven ground and cross-slopes
Biomechanical measures: Medial/Lateral Margin of Stability (MOS)
Correlation between prosthetic foot sagittal and coronal plane stiffness properties and Medial/Lateral Margin of Stability (MOS) during walking on uneven ground and cross-slopes
Performance-based outcomes: Narrowing Beam Walking Test
Correlation between prosthetic foot sagittal and coronal plane stiffness properties and Narrowing Beam Walking Test score.
Performance-based outcomes: Narrowing Beam Walking Test
Correlation between prosthetic foot sagittal and coronal plane stiffness properties and Narrowing Beam Walking Test score.
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Seattle Institute for Biomedical and Clinical Research
Lead sponsor
VA Puget Sound Health Care System
Collaborator
Minneapolis Veterans Affairs Medical Center
Collaborator
University of Chicago
Collaborator
