Intra-rater and inter-rater reliability of robotic arthrometer DYNEELAX®.

ABSTRACT

Purpose: The purpose of our study was to test the intra-rater and inter-rater reliability of the DYNEELAX® arthrometer in healthy subjects. Since rotational laxity will be measured for the first time in humans, indications for normative values will also be presented. Methods: Knee anterior laxity and rotational laxity using a DYNEELAX® arthrometer were assessed in 73 subjects (39 females and 34 males). An intraclass correlation coefficient was calculated to evaluate the intra-rater and inter-rater reliability of the DYNEELAX®. Results: An intraclass correlation coefficient for intra-rater reliability ranges from 0.631 (95% confidence interval; [CI] 0.47-0.75) to 0.699 (95% CI 0.56-0.80) and from 0.916 (95% CI 0.87-0.95) to 0.94 (95% CI 0.91-0.96) for anterior knee laxity and rotational knee laxity, respectively. An intraclass correlation coefficient for inter-rater reliability ranges from 0.578 (95% CI 0.40-0.71) to 0.646 (95% CI 0.44-0.78) and from 0.822 (95% CI 0.57-0.91) to 0.933 (95% CI 0.89-0.96) for anterior knee laxity and rotational knee laxity, respectively. Conclusions: The DYNEELAX® arthrometer has good to excellent intra-rater and inter-rater reliability for rotational knee laxity and moderate intra-rater reliability for anterior knee laxity in healthy subjects. Future studies should investigate the clinical significance of anterior and rotational laxity measured with the DYNEELAX® arthrometer in patients with knee pathology, as both laxities are critical for assessing the integrity of the intra-articular structures of the knee in clinical practice. Level of evidence Level IV.