2023 ISAKOS Biennial Congress ePoster
Reliability of the KNEELAX3 Arthrometer for Anterior Knee Laxity Measurement in Healthy Female Subjects
Azusa Saito, PT,BSc, Tokyo JAPAN
Shota Mashimo, PT, BSc, Akashi-Cho, Chuo-Ku, Tokyo JAPAN
Junya Kubota, PT, BSc, Tokyo JAPAN
Hiroyuki Sato, PT, BSc, Tokyo JAPAN
Fumiya Naonaga, PT,BSc, Tokyo JAPAN
Keita Tanaka, PT, BSc, Tokyo JAPAN
Erina Murosaki, PT,BSc, Tokyo JAPAN
Nobuto Kitamura, MD, PhD, Tokyo JAPAN
St. Luke’s International Hospital, Tokyo, JAPAN
FDA Status Cleared
Summary
This study suggested that there were good intra-rater reliability and moderate to good inter-rater reliability of measuring anterior tibial translation using the KNEELAX3, but the fixed error was found between one examiner and others. Standardization of measurement techniques should be considered.
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Abstract
Background
Commercially available knee arthrometers have been widely used to measure knee ligament stability to diagnose and evaluate the degree of anterior cruciate ligament (ACL) injuries. KNEELAX3 is a device to measure anterior tibial translation (ATT) in millimeters recording procedure with computerized software. The aims of this study were to measure ATT of healthy Japanese women using KNEELAX3 and to determine the reliability and validity of the KNEELAX3.
Methods
Sixty healthy Japanese women with no history of knee pathology (mean age 27.0 ± 3.6years) were included in this study. Three examiners (A, B, C), who were skilled in the use of KNEELAX3, measured the ATT. Each subject was positioned supine on an examination table with the knee in approximately 20 degrees of flexion. The ATT measurement was performed and recorded at 132N. For calculation of mean values and analysis of intra-rater reliability, examiner A took measurements two times on the same subjects on different days. For analysis of inter-rater reliability, three examiners measured on the same day. In order to analyzed inter-rater and intra-rater reliability, the intraclass correlation coefficient (ICC) was performed, and Bland-Altman (BA) analysis was used to determine the systematic error.
Results
Mean ATT was 5.5±1.9mm on the right side and 6.5±1.9mm on the left side. The ICC (95% CI) for intra-rater reliability were 0.77 (0.64-0.85) on the right and 0.87 (0.80-0.92) on the left. Based on the results of BA analysis, there was no systematic error and the MDC95 were 1.73mm on the right and 0.95mm on the left. The ICC for inter-rater reliability were 0.71-0.82 (0.25-0.89) on the right and 0.83-0.89 (0.63-0.89) on the left. The BA analysis showed the fixed error in the right knee between examiner A and the other examiner, while there were no systematic errors between other examiners. The ICC for side-to-side difference were 0.60-0.71, and MDC95 were 2.15-2.70: The fixed error was observed for examiner A, but no fixed error was confirmed for other examiners. No proportional error was observed in any of the measurements for each analysis.
Conclusion
This study demonstrated that there were good intra-rater reliability and moderate to good inter-rater reliability of measuring ATT using the KNEELAX3. However, the fixed error was found between one examiner and others, whereas no proportional error was found in any of the measurements. There was no deviation proportionally to the true value or occurred in a specific direction. Therefore, it may be possible to minimize the error by practice or repeating the measurement. Based on the results in this study, the measurement of ATT with use of KNEELAX3 is reliable, but the measurement technique should be standardized and established in consideration of the physical characteristics of the subjects to minimize the measurement errors.