Effects of activity intensity, time, and intermittent doffing on daily limb fluid volume change in people with transtibial amputation

Abstract

Background:: The volume of a prosthesis user's residual limb changes during the day and may affect the fit of the prosthesis. These changes must be managed by the user to prevent discomfort, skin breakdown, and falls.

Objectives:: The objectives were to test how activity, time of day, and intermittent doffing affected residual limb fluid volume in people with transtibial amputation.

Study design:: Standardized, repeated measure (A-B-A) out-of-laboratory protocol.

Methods:: Participants with transtibial amputation completed three 6-h test sessions. Two sessions served as controls (A protocol) during which participants left their prosthesis donned, and one session was an intervention (B protocol) where participants doffed their prosthesis twice for 20 min during the 6 h of testing. Within-socket fluid volume was measured using a custom portable bioimpedance analysis system.

Results:: A total of 13 participants completed the study. The rate of limb fluid volume loss was higher early in the session compared with late in the session. Participants experienced less fluid volume loss during high activity than low activity. Socket users with pin suspension experienced less posterior fluid volume loss when they intermittently doffed their prosthesis. Intermittent doffing did not benefit limb fluid volume of mechanical vacuum and suction suspension users.

Conclusion:: High activity may reduce fluid volume loss compared with low activity. Intermittent doffing may provide volume accommodation for transtibial prosthesis users with pin suspension.

Clinical relevance: Prosthetists should query their patients about the intensity of activity they conduct when advising them on limb volume management. Patients using sockets with pin suspension may be able to offset limb fluid volume loss by periodically doffing the prosthesis.

Keywords: Prosthetic interface mechanics; biomechanics; biomechanics of prosthetic/orthotic devices; prosthetic design; prosthetics; skin; skin stress.

Figures

Figure 1.

Electrode layout (left) and participant wearing portable bioimpedance monitoring system (right).

Figure 2.

Study protocol. Each cycle consisted of two low-activity intervals (L1 and L2) and one high-activity interval (H).

Figure 3.

Rates of percent limb fluid volume change during each cycle for the posterior (left) and anterior (right) regions. *Statistical significance.

Figure 4.

Rates of percent limb fluid volume change for low activity (L2) and high activity (H) for each cycle. Data from the posterior (left) and anterior (right) regions are shown. *Statistical significance.

Figure 5.

Percent limb fluid volume change for a participant demonstrating fluid volume gains during high activity (H) and losses during low activity (L1, L2). Data from equal weight-bearing stand points are shown.

Figure 6.

Short-term and long-term effect of intermittent doffing for posterior and anterior regions in sockets with pin (upper) and vacuum or suction (lower) suspension. “Benefit” occurred when the experimental session (B) rate of change was higher (less negative) than both control session rates of change (A1, A2), B > A1 and B > A2. “No Effect” was indicated by the experimental session rate of change in between control session rates of change, B > A1 and B A2. When the experimental session rate of change was lower (more negative) than both control session rates of change, B