Return to Sports
Limited strength evidence does not support waiting a specific time from surgery/ injury, or achieving a specific functional goal prior to return to sports participation after ACL injury or reconstruction.

Rationale
The rationale for return to play and secondary injury risk was based on one low and one very low strength study.37, 104 Early return (mean five months) versus late return (mean nine months) to sport was not different for subsequent ipsilateral ACL injury, subjective and objective functional outcomes or knee laxity. 37 Similarly, early return to sports (<6 months versus >6months) was not associated with increased incidence of either contralateral or ipsilateral ACL injury. 104

The rationale for return to play based on achieving functional criteria was based on one low strength study.11 This study reported similar potential return to pre-injury sport levels in those who attempted to return before 12 months relative to those who returned after 12 months.

Potential Harms of Implementation
As individuals heal and recover at different rates and each injury has its own unique circumstances, it is difficult to assign a specific endpoint that would favor return to sport.  Each patient should be treated individually and functionally advanced to the level of their ability. Premature return to full activity may cause injury to a reconstructed ligament, surrounding structures, or the contralateral knee.  Early return in those individuals who elect non-operative management may lead to further injury of surrounding tissues and further decline. Current evidence is lacking as to the long-term consequences of premature return to sport on joint homeostasis, dynamic function, and risk of secondary injury.

Future Research
Future research is needed to identify the functional deficits that are associated with increased second injury risk and reduced long term outcomes. Future investigations may assess more directly individual graft healing times, alternative therapeutic exercises, changes in frequency or duration to individual programs, platelet rich plasma treatments, genetic markers/gene therapy.