Effectiveness of elevated vacuum and suction prosthetic suspension systems in managing daily residual limb fluid volume change in people with transtibial amputation

Abstract

Previous studies investigating limb volume change with elevated vacuum have shown inconsistent results and have been limited by out-of-socket volume measurements and short, single-activity protocols. To evaluate the effectiveness of elevated vacuum for managing limb fluid volume compared to suction suspension with an in-socket measurement modality during many hours of activity. Fixed-order crossover design with a standardized out-of-laboratory activity protocol. Transtibial electronic elevated vacuum users participated in two sessions. Elevated vacuum was used during the first session, and suction suspension in the second. Participants completed a 5.5-h protocol consisting of multiple intervals of activity. In-socket residual limb fluid volume was continuously measured using a custom portable bioimpedance analyzer. A total of 12 individuals participated. Overall rate of fluid volume change was not significantly different, though the rate of posterior fluid volume change during Cycle 3 was significantly lower with elevated vacuum. Although individual results varied, 11 participants experienced lower overall rates of fluid volume loss in at least one limb region using elevated vacuum. Elevated vacuum may be more effective as a volume management strategy after accumulation of activity. Individual variation suggests the potential to optimize the limb fluid volume benefits of elevated vacuum by reducing socket vacuum pressure for some users. A better understanding of how elevated vacuum (EV) affects residual limb fluid volume will allow prosthetists to make more informed clinical decisions regarding accommodation strategies designed to improve daily socket fit.