Evaluation of Knee Flexion Angle During Gait in Knee Osteoarthritis Patients Using Inertial Measurement Unit and Sensor Fusion

Abstract

Knee osteoarthritis (OA) is one of the most common musculoskeletal diseases, and the number of patients is expected to increase in Japan. In recent years, gait analysis using inertial measurement units (IMUs) has been attracting attention. In this study, we quantified the knee flexion angle during gait in patients with knee OA using IMUs and sensor fusion considering centrifugal and tangential acceleration. And we compared the results between healthy participants and patients with knee OA to validate the usefulness of the system. As a sensor fusion, an extended kalman filter was constructed to correct the posture of IMUs using the corrected values of centrifugal and tangential acceleration using the accelerometer and gyroscope. Gait measurement experiments were conducted on healthy participants and patients with knee OA mounting IMUs. As a result, estimated knee flexion angle during gait of patients with knee OA showed patient-specific waveform flattening and amplitude changes different from those of healthy participants, indicating that is useful for clinical gait analysis.