Does actively enlarging socket volume during resting facilitate residual limb fluid volume recovery in trans-tibial prosthesis users?

Background: Residual limb volume loss is a source of prosthetic socket fit problems in people with lower-limb amputation. The aim of this study was to investigate a novel volume recovery strategy for people with trans-tibial amputation.

Methods: Test sockets for people with trans-tibial amputation were created that allowed panels of an adjustable socket and the underlying elastomeric liner to be pulled radially outward, using small motors mounted to the socket. One Control and one Intervention session were conducted with each participant. During Intervention sessions, panel-pull was executed during the sits of a multi-cycle sit/walk protocol. No panel-pull was executed during the Control sessions. Residual limb fluid volume was monitored in anterior and posterior regions using bioimpedance analysis.

Findings: Results from 12 participants demonstrated that short-term (12 min after the intervention was applied) median posterior residual limb fluid volume change for Intervention (0.44%) was higher than that for Control (-0.02%) (P = .015). Long-term (40 min after the intervention was applied) median posterior residual limb fluid volume change for Intervention (0.95%) was higher than that for Control (-0.26%) (P = .002).

Interpretation: If a panel-pull mechanism that was easy to assemble and operate could be created, then panel-pull may be an effective accommodation strategy to reduce daily limb volume loss in trans-tibial prosthesis users.