In a study by Straaten et al., the inertial sensor system was capable of accurately distinguishing between movement characteristics of healthy controls and PwKOA (persons with knee osteoarthritis). Further, significant relationships were established between perceived pain, fear of movement, and joint motion. This study was conducted to investigate the ability of inertial sensors to make a distinction between HC and PwKOA.

It also determined the correlation between pain-related factors, disability scores, and movement behaviour. A total of 12 HC and 19 PwKOA were enrolled in this study. A camera-based motion analysis system and the inertial sensor system recorded 5 repetitions of 6 functional movement tasks simultaneously (forward and sideward lunge, walking, ascent and descent stairs, single-leg squat, sit-to-stand).

Utilizing SPM1D (one-dimensional statistical parametric mapping), substantial differences in angular waveforms of trunk, pelvis, and lower limb joints between PwKOA and HC were examined. The association existing between discriminating joint motion, pain-related factors, and disability utilizing spearman’s correlation coefficients were determined.

PwKOA demonstrated considerably less internal pelvis rotation, trunk rotation, and knee flexion ROM (Range of motion) during walking as illustrated in Table 1:

Moreover, reduced knee flexion was associated with a higher level of perceived pain. During the sideward lunge, PwKOA subjects demonstrated lower ankle plantar flexion, knee flexion, and hip abduction as depicted in Table 2:

This diminished hip abduction was associated with higher movement fear. During forward lunge, single-leg squat, and ascent and descent stairs, PwKOA had considerably diminished knee flexion (Table 3). 

There were no significant correlations witnessed with disability. Further research should aim to enhance the assessment of small movement deviations in clinically relevant tasks.