# A Low-Cost, Practical Fitness Monitor of Socket-Suspension Systems for Lower Limb Amputees

> **NIH NIH R43** · ASSIST EQUIPMENT DEVELOPMENT, INC. · 2022 · $225,397

## Abstract

A low-cost, easy-to-use fit monitor of socket-suspension systems for lower
 limb amputees
For lower limb amputees, the use of prosthetic legs is critical to remain active and live independently. Interface
between the residual limb and the prosthetic leg, usually a prosthetic socket with related suspension system (SSS),
only works well if the SSS is fit appropriately. To maintain an appropriate SSS fit, repeated interventions from
both amputees and clinicians are necessary; otherwise, the SSS fit deteriorates due to fluctuation of amputees’
residual limb volume caused by long term factors, such as body weight changes, and short-term factors, such as
impact during locomotion. Currently, all interventions are guided by amputees’ haptic sensation, which is not a
reliable information source for regulation of the SSS fit. Guided by this inaccurate information source,
interventions are often not effectively or timely, and deterioration of the SSS fit is often ignored until side effects
become severe. These unfavorable side effects include unexpected stress concentrated on the residual limb,
abnormal gait patterns, increased risk of secondary conditions such as back pain, and skin abrasions that are
painful and difficult to heal.
Objective of the proposal is to develop a novel SSS fit monitor to track the SSS fit based on kinematic features of
pistoning, which describes the relative motion between the residual limb and the prosthetic socket. We will
accomplish our study objectives by pursuing three specific aims.
Aim 1: Identify phase-dependent kinematic features of pistoning, which are sensitive to change of SSS fit, on
multiple locations on the residual limb; Aim 2: Design a sensor array to track pistoning motions in 3D space; and
Aim 3: demonstrate the capability to monitor SSS fit during walking on amputee subjects using the developed
SSS fit monitor.
All these efforts will help us to reach our long-term goal: help amputees and clinicians to improve their capability
to manage the interface between the residual limb and their prosthetic legs.

## Key facts

- **NIH application ID:** 10384774
- **Project number:** 1R43HD105511-01A1
- **Recipient organization:** ASSIST EQUIPMENT DEVELOPMENT, INC.
- **Principal Investigator:** Ming Liu
- **Activity code:** R43 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $225,397
- **Award type:** 1
- **Project period:** 2022-05-01 → 2023-11-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10384774

## Citation

> US National Institutes of Health, RePORTER application 10384774, A Low-Cost, Practical Fitness Monitor of Socket-Suspension Systems for Lower Limb Amputees (1R43HD105511-01A1). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10384774. Licensed CC0.

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