Comparison of quantitative evaluation between cutaneous and transosseous inertial sensors in anterior cruciate ligament deficient knee: A cadaveric study

Abstract Background Recently several authors have reported on the quantitative evaluation of the pivot-shift testusing cutaneousfixation of inertial sensors. Before utilizing this sensor for clinical studies, it is necessary to evaluate the accuracy of cutaneoussensor in assessing rotational knee instability. To evaluate the accuracy of inertial sensors, we compared cutaneousand transosseous sensors in the quantitative assessment of rotational knee instability in a cadaveric setting, in order to demonstrate their clinical applicability. Methods Eight freshly frozen human cadaveric knees were used in this study. Inertial sensors were fixed on the tibial tuberosityand directly fixed to the distal tibia bone. A single examiner performed the pivot shift testfrom flexion to extension on the intact knees and ACL deficient knees. The peak overall magnitude of acceleration and the maximum rotational angular velocity in the tibial superoinferior axis was repeatedly measured with the inertial sensor during the pivot shift test. Correlations between cutaneousand transosseous inertial sensors were evaluated, as well as statistical analysis for differences between ACL intact and ACL deficient knees. Results Acceleration and angular velocity measured with the cutaneoussensor demonstrated a strong positive correlation with the transosseous sensor (r = 0.86 and r = 0.83). Comparison between cutaneousand transosseous sensor indicated significant difference for the peak overall magnitude of acceleration ( cutaneous: 10.3 ± 5.2 m/s 2 , transosseous: 14.3 ± 7.6 m/s 2 , P Conclusions There is a positive correlation between cutaneousand transosseous inertial sensors. Therefore, this study indicated that the cutaneousinertial sensors could be used clinically for quantifying rotational knee instability, irrespective of the location of utilization.