Anterior knee laxity and ACL magnetic resonance signals in healthy and ACL-reconstructed knees following exercise.

Abstract

Objective: The study compared anterior knee laxity and anterior cruciate ligament magnetic resonance signals between healthy and anterior cruciate ligament reconstruction (ACLR) knees after exercise to verify differences. This research can guide future training to reduce the risk of reinjury.

Materials and methods: Fifty-four male footballers between June and August 2022 were enrolled in this case-control study. Subjects who underwent ACLR in the previous 3 years (study group) were compared with healthy volunteers (control group). Each group consisted of twenty-seven patients. Data recorded were anterior tibial translation (ATT) expressed in millimeters using an arthrometer and the ratio of ACL to fat tissue signal intensity using magnetic resonance imaging. Measurements were collected at T0 (at rest), T1 (after 40 minutes of linear running of 3.5 miles), and T2 (after 90 minutes of a regular football match).

Results: No statistical difference was observed in demographic pre-analysis features. No difference was indicated between the two groups according to ATT. Conversely, ACL natives demonstrated significant increases in the ratio of ACL to fat tissue signal intensity when compared with ACLR in the three different measurements. Regarding differences within each group, we demonstrated that anterior knee laxity increased in both groups after 90 minutes of a regular football match. The ACL MRI signal did not differ in the study group, but it increased in the control group after exercise.

Conclusions: Although exhibiting distinct MRI signals, ACL-reconstructed tendons show similar post-exercise joint laxity as healthy ligaments. Looking ahead, leveraging specific insights could help tailor training sessions for preventive purposes.