A human motion capture system using an RGB-D camera could be a good option to understand the trunk limitations in
spondyloarthritis. The aim of this study is to validate a human motion capture system using an RGB-D camera to analyse
trunk movement limitations in spondyloarthritis patients. Cross-sectional study was performed where spondyloarthritis
patients were diagnosed with a rheumatologist. The RGB-D camera analysed the kinematics of each participant during seven
functional tasks based on rheumatologic assessment. The OpenNI2 library collected the depth data, the NiTE2 middleware
detected a virtual skeleton and the MRPT library recorded the trunk positions. The gold standard was registered using an
inertial measurement unit. The outcome variables were angular displacement, angular velocity and lineal acceleration of the
trunk. Criterion validity and the reliability were calculated. Seventeen subjects (54.35 (11.75) years) were measured. The
Bending task obtained moderate results in validity (r=0.55–0.62) and successful results in reliability (ICC=0.80–0.88) and
validity and reliability of angular kinematic results in Chair task were moderate and (r=0.60–0.74, ICC=0.61–0.72). The
kinematic results in Timed Up and Go test were less consistent. The RGB-D camera was documented to be a reliable tool
to assess the movement limitations in spondyloarthritis depending on the functional tasks: Bending task. Chair task needs
further research and the TUG analysis was not validated.
