Related Experiment Video
Updated: Jul 6, 2026
Using a Knee Arthrometer to Evaluate Tissue-specific Contributions to Knee Flexion Contracture in the Rat
Published on: November 9, 2018
Rotational knee laxity: reliability of a simple measurement device in vivo
Andrew G Tsai1, Volker Musahl, Hanno Steckel
1Department of Orthopaedic Surgery, University of Pittsburgh, Pittsburgh, PA, USA. andrew.g.tsai@gmail.com
Background:
Double bundle ACL reconstruction has been demonstrated to decrease rotational knee laxity. However, there is no simple, commercially-available device to measure knee rotation. The investigators developed a simple, non-invasive device to measure knee rotation. In conjunction with a rigid boot to rotate the tibia and a force/moment sensor to allow precise determination of torque about the knee, a magnetic tracking system measures the axial rotation of the tibia with respect to the femur. This device has been shown to have acceptable levels of test re-test reliability to measure knee rotation in cadaveric knees.
Methods:
The objective of this study was to determine reliability of the device in measuring knee rotation of human subjects. Specifically, the intra-tester reliability within a single testing session, test-retest reliability between two testing sessions, and inter-tester reliability were assessed for 11 male subjects with normal knees.
Results:
The 95% confidence interval for rotation was less than 5 degrees for intra-tester, test-retest, and inter-tester reliability, and the standard error of measurement for the differences between left and right knees was found to be less than 3 degrees .
Conclusion:
It was found that the knee rotation measurements obtained with this device have acceptable limits of reliability for clinical use and interpretation.
