Prospective cohort study of 159 young athletes (ages 15-30) after primary ACL reconstruction. Examined whether timing of return to sport, muscle function symmetry, and quadriceps strength symmetry predict second ACL injury. Used Cox proportional hazard regression to analyze time-to-event outcomes from a rehabilitation registry.
The dominant teaching in ACL rehabilitation has been that passing functional criteria — hop tests, quadriceps symmetry. Is the key gate for safe return to sport. This paper challenges that directly: in young athletes, the 9-month time threshold was a far stronger predictor of reinjury than any functional test result.
When a 19-year-old soccer player passes their hop battery at 7.5 months and wants to return, the answer is not yet. Regardless of their LSI. The 9-month mark is the evidence-based minimum, and 67% of reinjuries in this cohort came from athletes who returned in that 8-to-9-month danger zone.
Counsel patients explicitly that functional tests are a floor, not a ceiling, and that time is an independent requirement. For your highest-level athletes (TAS 9-10), the reinjury risk approaches 25%. Set that expectation early and revisit it at every follow-up visit.
Prospective cohort study of 159 young athletes (ages 15-30) after primary ACL reconstruction. Examined whether timing of return to sport, muscle function symmetry, and quadriceps strength symmetry predict second ACL injury. Used Cox proportional hazard regression to analyze time-to-event outcomes from a rehabilitation registry.
The dominant teaching in ACL rehabilitation has been that passing functional criteria — hop tests, quadriceps symmetry. Is the key gate for safe return to sport. This paper challenges that directly: in young athletes, the 9-month time threshold was a far stronger predictor of reinjury than any functional test result.
When a 19-year-old soccer player passes their hop battery at 7.5 months and wants to return, the answer is not yet. Regardless of their LSI. The 9-month mark is the evidence-based minimum, and 67% of reinjuries in this cohort came from athletes who returned in that 8-to-9-month danger zone.
Counsel patients explicitly that functional tests are a floor, not a ceiling, and that time is an independent requirement. For your highest-level athletes (TAS 9-10), the reinjury risk approaches 25%. Set that expectation early and revisit it at every follow-up visit.