How Do Socket Size Adjustments during Ambulation Affect Residual Limb Fluid Volume? Case Study Results

Abstract

ABSTRACT Introduction Adjustable prosthetic sockets may be useful in management of limb volume in individuals with amputation. Incrementally increasing socket size during ambulation may increase residual limb fluid volume, deterring daily volume loss without sacrificing gait stability. Materials and Methods Participants with transtibial limb loss wore motor-controlled cabled-panel adjustable sockets while residual limb fluid volume was monitored using bioimpedance analysis. Participants walked on a treadmill with a safety harness while socket size was adjusted to establish users' ranges of acceptable sizes and optimal size. Then single controlled size adjustments were made. In longer duration testing outside the laboratory, participants used a portable system controlled by a mobile phone app to incrementally increase or decrease their socket size. Results For the two participants tested, comfortable socket sizes spanned as low as a 1.6% range of socket volume to as high as a 6.1% range. Limb fluid volume changed in proportion to socket size when adjustments were near users' optimal socket size setting. Conclusions Adjustable sockets are a viable means to manipulate limb fluid volume during ambulation. Incremental changes in socket size, approximately 0.33% socket volume, were sufficient to induce detectable changes in socket fit.