Article

OBJECTIVE: To investigate the effect of a vacuum-assisted socket suspension
system as compared with pin suspension on lower extremity amputees. DESIGN:
Randomized crossover with 3-week acclimation. SETTING: Household, community, and
laboratory environments. PARTICIPANTS: Unilateral, transtibial amputees (N=20
enrolled, N=5 completed). INTERVENTIONS: (1) Total surface-bearing socket with a
vacuum-assisted suspension system (VASS), and (2) modified patellar
tendon-bearing socket with a pin lock suspension system. MAIN OUTCOME MEASURES:
Activity level, residual limb volume before and after a 30-minute treadmill walk,
residual limb pistoning, and Prosthesis Evaluation Questionnaire. RESULTS:
Activity levels were significantly lower while wearing the vacuum-assisted socket
suspension system than the pin suspension (P=.0056; 38,000 +/- 9,000 steps per 2
wk vs 73,000 +/- 18,000 steps per 2 wk, respectively). Residual limb pistoning
was significantly less while wearing the vacuum-assisted socket suspension system
than the pin suspension (P=.0021; 1 +/- 3mm vs 6 +/- 4mm, respectively).
Treadmill walking had no effect on residual limb volume. In general, participants
ranked their residual limb health higher, were less frustrated, and claimed it
was easier to ambulate while wearing a pin suspension compared with the VASS.
CONCLUSIONS: The VASS resulted in a better fitting socket as measured by limb
movement relative to the prosthetic socket (pistoning), although the clinical
relevance of the small but statistically significant difference is difficult to
discern. Treadmill walking had no effect, suggesting that a skilled prosthetist
can control for daily limb volume fluctuations by using conventional, nonvacuum
systems. Participants took approximately half as many steps while wearing the
VASS which, when coupled with their subjective responses, suggests a preference
for the pin suspension system.
CI - Copyright (c) 2011 American Congress of Rehabilitation Medicine. Published by
Elsevier Inc. All rights reserved.

Langue : ANGLAIS