Patient Selection

The inclusion criteria for the study were as follows: primary single-bundle ACL reconstruction, age younger than 20 years at surgery, normal contralateral knee (no previous knee surgery), routine follow-up at 12 months postoperatively, and a return to preinjury sport at either a lower or the same level at some time following surgery. From a clinical practice database, we identified a cohort of 623 patients who had undergone single-bundle primary ACL reconstruction surgery between May 2005 and October 2015. There were no or incomplete 12-month clinical follow-up data for 129 patients, of whom 39 had already sustained a second ACL injury prior to the 12-month clinical review (25 ruptures, 14 contralateral ACL). We were unable to contact 85 patients for longer term (+3 years) follow-up to determine if a subsequent ACL injury had occurred. Full data were therefore available for 409 patients, of whom 80 had not made any return to sport, resulting in 329 patients in the final study cohort (Figure 1).

Flow diagram of patient selection. ACL, anterior cruciate ligament.