Reliability of kinematic waveforms during gait analysis with total hip arthroplasty patients

Purpose: The aim of the study was to determine the test-retest reliability of lower limb kinematic waveforms derived from 3D gait analysis (3DGA) in patients following total hip arthroplasty (THA). Methods: Eight (7 ​M:1F; age: 70 ​± ​7 years; height: 1.68 ​± ​0.11 ​m; mass: 85 ​± ​20 ​kg) adults with a unilateral THA attended test and retest sessions. 3DGA was undertaken with participants walking at a self-selected pace along a 7 ​m walkway within each session. The standard error or the measurement (SEM) was calculated for hip, knee and ankle joint angles in all three planes, over the walking gait cycle. Results: The SEM ranged from 2.9 to 4.1°, 2.7–3.7° and 1.9–3.9°, in the sagittal, frontal and traverse planes at the hip. At the knee the SEM ranged from 1.6 to 4.2°, 1.0–1.9° and 1.3–2.9° in the sagittal, frontal and transverse planes, respectively. While the SEM ranged from 0.7 to 2.0°, 1.2–2.3° and 2.9–4.0° in the sagittal, frontal and transverse planes at the ankle. Conclusions: The findings demonstrate that 3DGA provides a reliable means of quantifying lower limb kinematics over the walking gait cycle in patients following THA, with all SEM values below the 5° threshold previously suggested to identify clinically meaningful differences. The SEM values reported may aid in the interpretation of changes in lower limb kinematics in patients following THA.