After ACL Reconstruction: How Persistent Are Limb Deficits?

Between-limb deficits remain for more than nine months after anterior cruciate ligament reconstruction (ACLR), affecting soccer players’ performance, a new study finds.

The study, “Lower Limb Kinetic Asymmetries in Professional Soccer Players With and Without Anterior Cruciate Ligament Reconstruction: Nine Months Is Not Enough Time to Restore ‘Functional’ Symmetry or Return to Performance,” was published online in The American Journal of Sports Medicine on April 15, 2020.

The impetus of the study was the concern that residual between-limb deficits were affecting soccer players’ performance after ACLR.

To see if this was in fact true, the researchers analyzed the movement strategies of athletes recovering from ACLR at different milestones during rehabilitation. Specifically, they compared the recovering athletes’ kinetic parameters during a countermovement jump with a force platform to the kinetic parameters of healthy soccer players.

Overall, 370 male professional soccer players were divided into four groups: group 1 (<6 months post-ACLR), group 2 (6-9 months post-ACLR), group 3 (>9 months post-ACLR), and group 4 (healthy matched controls).

The researchers found that while the injured players were able to increase their jump performance in the later stages of rehabilitation. Lower limb deficits were still present, with effect sizes ranging from moderate to very large (d = 0.42-1.35). Even greater than nine months out, they were still there, although smaller.

The biggest differences were seen in concentric impulse, concentric peak force, eccentric deceleration impulse, and eccentric deceleration rate of force development asymmetry (p < .05).

Concentric impulse asymmetry had the strongest association with a history of ACLR.

The researchers wrote, “Between-limb deficits in key eccentric and concentric loading parameters remain > 9 months after ACLR, indicating a compensatory offloading strategy to protect the involved limb during an athletic performance task. Concentric impulse asymmetry could be considered an important variable to monitor during rehabilitation.”