Functional Performance Evaluation of the Northwestern University Flexible Sub-Ischial Vacuum (NU-FlexSIV) Socket for Persons With Transfemoral Amputation

The proposed clinical trial will be an assessor-blinded prospective randomized cross-over trial wherein participants with unilateral transfemoral amputation will be randomized to using one of two socket conditions (i.e., sub-ischial or ischial containment) before crossing over to the other socket condition. Random allocation (computer-generated) utilizing blocks of random size will be used to assign the initial treatment condition. The trial will be balanced such that all subjects will receive all treatments (i.e., both socket conditions) and that all subjects will participate for the same number of periods (i.e., two). While a washout period is not strictly necessary, it is effectively included as subjects will need to transition back to their usual, pre-study socket/prosthesis while the second test socket is fabricated.

Allocation of intervention will be concealed from the investigators until after a subject is enrolled. The starting socket design will be enclosed in sequentially numbered, opaque, sealed envelopes. Envelopes will be opened sequentially and only after the participant's name and other details are written on the appropriate envelope.

Blinding of prosthetic interventions is challenging given that they are devices that must be custom-fabricated and donned each day by the subject. Hence, for this study only the assessor will be blinded. The blinded assessor will be responsible for administration of the clinical performance and patient-reported measures as well as processing of motion analysis data.