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

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.