# Use of Wearable Sensors to Assess Prosthetic Alignment in Veterans with Unilateral Transtibial Amputations

> **NIH VA I21** · VA EASTERN COLORADO HEALTH CARE SYSTEM · 2024 · —

## Abstract

Veterans with transtibial amputation require a prosthesis to walk and are at an increased risk of secondary
injury, discomfort, and reduced quality of life. Proper prosthetic alignment can reduce these risks and improve
functional ability and comfort in individuals with transtibial amputation. Currently, prosthetists (clinicians)
subjectively align a prosthesis, and this may require several clinical visits. Subjective alignment relies on
prosthetists’ experience and visual inspection of walking, which is prone to errors and time consuming. Thus,
there is an urgent need to develop objective tools for prosthesis alignment. We aim to develop a novel method
to [assess] prosthesis alignment accurately, precisely, and cost-efficiently using wireless sensor technology,
which could improve quality of life and reduce secondary injury risk for the millions of prosthesis users in the
United States. The goal of this study is to determine the accuracy and precision of using wearable sensors
combined with an algorithm to assess prosthesis alignment in 10 Veterans with transtibial amputation.
 [We will ask 10 Veterans with transtibial amputation to walk on a force-treadmill at 1.25 m/s while they use
a prosthesis with neutral alignment and that varies by 3° and 6° in one of three planes, the sagittal, coronal,
and transverse planes, for a total of 13 prosthesis alignments. For each alignment condition, we will determine
the accuracy and precision of using inertial measurement units (IMUs) combined with a numerical algorithm
to estimate dynamic-to-static angle (DSA) of the prosthesis and the biological shank during walking in 10
Veterans with unilateral transtibial amputation (Aim 1), where DSA provides information regarding the
orientation of the prosthesis and the biological shank. We will also determine the accuracy and precision of
using IMUs combined with a numerical algorithm to estimate inter-limb symmetry indices of step length, step
frequency, and contact time, which are important discrete temporal-spatial parameters during walking in 10
Veterans with unilateral transtibial amputation (Aim 2). We will compare results estimated using IMUs with
results calculated using traditional gold-standard measurements of 3D motion capture and ground reaction
forces. We will also investigate the association between angular changes in prosthesis alignment and DSA
and interlimb symmetry indices (Aim 3).] We hypothesize that the IMU method will provide accurate (root-
mean squared error [RMSE]<6°) and precise (inter-class correlation coefficient [ICC]>0.75) estimations of
DSA for both legs and inter-limb symmetry indices (mean absolute percentage error [MAPE]<10%, ICC>0.75)
of temporal-spatial parameters. We also hypothesize that changes in prosthesis alignment will result in
significant differences in DSA using the IMU method and motion capture measurements. We hypothesize
that changes in prosthesis alignment will result in significant differences in interlimb symmetry...

## Key facts

- **NIH application ID:** 11141544
- **Project number:** 5I21RX003861-03
- **Recipient organization:** VA EASTERN COLORADO HEALTH CARE SYSTEM
- **Principal Investigator:** Alena Grabowski
- **Activity code:** I21 (R01, R21, SBIR, etc.)
- **Funding institute:** VA
- **Fiscal year:** 2024
- **Award amount:** —
- **Award type:** 5
- **Project period:** 2022-07-01 → 2025-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/11141544

## Citation

> US National Institutes of Health, RePORTER application 11141544, Use of Wearable Sensors to Assess Prosthetic Alignment in Veterans with Unilateral Transtibial Amputations (5I21RX003861-03). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/11141544. Licensed CC0.

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