# Measuring in-socket residual limb volume fluctuation

> **NIH NIH R01** · UNIVERSITY OF WASHINGTON · 2024 · $628,514

## Abstract

Summary
The long-term goal of the proposed research is a paradigm shift towards limb size management rather than
socket size management in prosthesis users experiencing socket fit changes during the day. The focus of this
application is to implement and optimize a novel limb-volume management strategy, and then characterize its
impact on prosthesis user clinical outcomes, health, and quality-of-life.
The specific aims of the proposed research are to monitor user activity and socket fit within prostheses equipped
with novel socket release/relock mechanisms. Socket release is the relief of limb-socket pressures during sitting,
and relock is the return to the normal socket configuration. Different release/relock operations conducted while
sitting and their influence on subsequent ambulatory limb mechanics, socket fit, and functional outcomes are
tested. The procedure most beneficial to patient outcomes is implemented in long-term testing. Participants wear
prostheses with the socket release/relock mechanism in their free-living environments for four weeks. Outcome
measures are compared with results from traditional sockets.
To accomplish the aims, unobtrusive sensors that monitor prosthesis use and limb-socket distances indicative
of socket fit are integrated into prostheses with motor-driven socket release/relock mechanisms. A repeated-
measures study is conducted using a standardized protocol to determine if the ordering of pin relock and socket
relock after socket release affects subsequent limb fluid volume retention, limb vertical and angular positions in
the socket, user comfort, and functional performance. A crossover study is conducted to determine if use of
release/relock sockets compared with traditional sockets for 4 weeks enhances participant activity, socket fit,
self-reported outcomes, energy level, and residual limb health.
The relevance of the proposed application to public health is better understanding how use of active
release/relock affects users’ experience with a prosthesis, clinically-important outcomes related to residual limb
health, and users’ performance in life activities. Currently, it is unknown to what degree active release/relock
benefits prosthesis users’ quality of life. Potentially, the efforts described here can be extended to other areas
where devices require a secure and intimate fit with human tissues despite changes in soft tissue volume,
including trans-fermoral prosthetics, upper-limb prosthetics, and orthotics.

## Key facts

- **NIH application ID:** 10864992
- **Project number:** 5R01HD060585-12
- **Recipient organization:** UNIVERSITY OF WASHINGTON
- **Principal Investigator:** Joan E. Sanders
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $628,514
- **Award type:** 5
- **Project period:** 2009-09-10 → 2025-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10864992

## Citation

> US National Institutes of Health, RePORTER application 10864992, Measuring in-socket residual limb volume fluctuation (5R01HD060585-12). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10864992. Licensed CC0.

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