Nishida K, Matsushita T, Hoshino Y, et al. - In this study, the impacts of time from injury to surgery and meniscal injuries on knee rotational laxity in anterior cruciate ligament (ACL)-deficient knees using the electromagnetic system (EMS) retrospectively were evaluated. Researchers enrolled a total of 94 unilateral ACL-injured individuals (44 males and 50 females, mean age: 27.3 ± 11.8 years). They conducted the pivot-shift test, prior to ACL reconstruction, as was a quantitative evaluation applying EMS to ascertain tibial acceleration. Individuals were categorized into four groups according to the chronicity: group 1, within 3 months (22 patients); group 2, between 3 and 6 months (29 patients); group 3, between 6 and 12 months (23 patients); and group 4, more than 12 months (20 patients). The appearance of meniscal injuries was investigated arthroscopically. It was reported that rotational laxity increased with time and the increased rotational laxity was evidently more than 1 year after injury in ACL-deficient knees, while it increased with concomitant lateral meniscal injuries within 1 year after injury.