Objective: Investigate the effect of a brimless interface design compared with ischial ramus containment (IRC) of interfaces when using vacuum-assisted suspension (VAS) on transfemoral amputees (TFAs). Design: Randomized experimental crossover. Setting: Household, community, and clinic. Participants: Unilateral TFAs (N = 12 enrolled, N = 10 analyzed). Mean age: 42.9 years. Mean residual limb length: 60.3% of the sound side femur length. Participants' mean time as an amputee: 8.3 years and median AMP score: 43. Interventions: (1) IRC VAS interface, and (2) brimless VAS interface. Average medial wall height for IRC interfaces was 0.7 cm proximal to the distal-most aspect of the ischial tuberosity (IT). The medial wall on the brimless design was an average of 3.3 cm distal to the distal-most aspect of the IT. Main outcome measures: Spatiotemporal gait parameters, limits of stability, four square step test, and subjective perception using the prosthetic evaluation questionnaire (PEQ). Results: Step length was significantly improved towards the IRC (p = 0.04), when calculating degree of asymmetry. Base of support was significantly narrowed toward the brimless (p = 0.03). All subjective measures reached statistical significance in favor of improvement with the brimless design, compared to the IRC. Conclusions: The brimless design was equivalent to IRC in most gait and balance outcome measures. However, step length was more symmetrical toward the IRC while base of support was narrowed toward the brimless demonstrating mixed inconsistent performance changes. Further, the PEQ demonstrated significant subjective improvements in prosthetic related function and quality of life when participants used the brimless design. Brimless interface design may be a clinically viable choice. (C) 2014 Elsevier B.V. All rights reserved.
