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Predicting Severe Knee Arthritis Based on Two Inertial Measurement Unit Sensors as a Dynamic Coordinate System Using
Erfan Azizi1, Mohammadsadegh Darbankhalesi1, Amirhossein Zare2
1Department of Bioelectrics and Biomedical Engineering, School of Advanced Technologies in Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
Journal of Medical Signals and Sensors
|April 7, 2025
Summary
A wearable device using inertial measurement unit (IMU) sensors can accurately differentiate between healthy individuals and those with severe knee osteoarthritis (KOA). This non-invasive method shows promise for diagnosing KOA, offering an alternative to traditional X-rays.
Area of Science:
- Biomedical Engineering
- Orthopedics
- Wearable Technology
Background:
- Musculoskeletal disorders, particularly knee osteoarthritis (KOA), pose a significant healthcare challenge due to aging populations.
- Current KOA diagnosis relies on radiographs, which involve ionizing radiation and have drawbacks.
- There is a need for non-invasive, low-cost diagnostic methods for KOA.
Purpose of the Study:
- To evaluate the efficacy of a wearable device in distinguishing between healthy individuals and those with severe KOA (grade 4).
- To explore the potential of wearable sensor data for KOA diagnosis.
Main Methods:
- A wearable device with two inertial measurement unit (IMU) sensors (thigh and lower leg) was utilized.
- New features were extracted in a dynamic coordinate system from 1433 IMU signals from 15 healthy and 15 severe KOA individuals (aged >45).
- Four classifiers (naive Bayes, KNN, SVM, random forest) were evaluated using 10-fold cross-validation.
Main Results:
- The K-nearest neighbors (KNN) classifier achieved the highest accuracy at 93.71 ± 1.1%.
- KNN also demonstrated high precision at 93 ± 1.31%.
- The proposed algorithm showed improved sensitivity compared to existing methods.
Conclusions:
- Novel features derived from a dynamic coordinate system and the KNN model effectively diagnose between healthy individuals and KOA patients.
- The wearable device shows potential as an auxiliary tool for arthritis diagnosis.
- Further validation is needed, as results are specific to severe KOA (grade 4) and may differ for other grades.

