Validation and reliability of a novel portable automated knee arthrometer: a cadaveric study bridging the skin-to-bone gap and suggesting medial pivotal rotation as a superior marker for ACL deficiency

The arthrometer showed excellent reliability and acceptable validity for assessing AT, CAIR, and MPR. Although skin-referenced measurements differ from true osseous rotation, they may provide clinically meaningful assessments for within-subject comparisons. MPR increased more than CAIR after ACL sectioning, suggesting it may serve as a superior marker for ACL deficiency.