Introduction: Although current rehabilitation protocols following anterior cruciate ligament reconstruction (ACLR) are based on the graft remodeling process, there is uncertainty about its time schedule. Moreover, there are individual differences in neuromotor learning and flexibility after ACLR. The current study was conducted to investigate the functional outcomes of the criterion-based rehabilitation protocol in amateur athletes following ACLR.

Methods: Fifty amateur male athletes who had ACLR were assigned randomly into two equal groups. The experimental group received a criterion-based rehabilitation protocol. The control group received a conventional physical therapy program. Both groups had five treatment sessions per week for six months. The primary outcome was pain intensity measured by VAS. Secondary outcomes included functional assessments measured by the limb symmetry index (LSI) of the hop test battery, knee effusion, and the Knee injury and Osteoarthritis Outcome Score (KOOS).

Results: Mixed-design-MANOVA indicated significant treatment, time, and treatment × time interaction. The interaction was significant for all outcome measures in favor of subjects who received a criterion-based rehabilitation protocol. Within-group analysis revealed a significant reduction in pain in both groups and improvements in all variables related to the KOOS or LSI of the hop test battery. Knee effusion was significantly reduced post-treatment in patients who received a criterion-based protocol when compared to their controls.

Conclusions: Although application of a criterion-based rehabilitation protocol for 6 months after ACLR is more effective than a conventional program, its duration should be expanded beyond this period to allow patients to reach their return to play goals.