As a physical therapist, I get this question often. Working with athletes of all ages, there are certain differences in timelines - but this includes a variety of factors. A high school athlete wanting to get back to another season of football and a 26 year old office worker who does crossfit or lifts regularly and runs recreationally are two very different worlds.
The short answer:
As a general rule, the average time for an athlete to return to sports after an ACL repair is generally around 9 to 12 months post-surgery, though this varies based on individual recovery rates, rehabilitation progress, and sport demands. Current evidence suggests that returning before 9 months may increase the risk of re-injury. However, some athletes with excellent strength, stability, and movement control may be cleared as early as 6 months.
The return-to-sport timeline is usually guided by a combination of objective criteria, including:
Strength Tests including maximum force testing measurements.
Hop tests including performance testing in the clinic.
Psychological readiness, and the absence of knee pain or swelling.
Most research now emphasizes a "criteria-based" rather than strictly "time-based" approach, as outcomes are generally better when athletes meet specific functional benchmarks rather than rushing to meet a timeline.
What are the specific studies that cite this return to sport timeline? What does the statistics out there look like?
Several key studies provide evidence for the recommended 9 to 12-month return-to-sport (RTS) timeline post-ACL reconstruction (ACLR), often emphasizing a criteria-based approach over a strict timeline. Here are some influential studies:
Grindem et al. (2016)Study Title: "Simple decision rules can reduce reinjury risk by 84% after ACL reconstruction: the Delaware-Oslo ACL cohort study"Findings: This prospective study found that athletes who returned to sports at 9 months or later post-surgery had a significantly lower re-injury risk. The study highlighted the importance of meeting functional criteria (strength and hop tests) before return to sport.
Beischer et al. (2020)Study Title: "Young Athletes at Risk of Early Reinjury Following Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-analysis"Findings: This meta-analysis of 48 studies showed a high rate of re-injury among athletes who returned to sport before 9 months post-ACLR. It supported waiting 9–12 months to reduce the risk, especially for younger athletes.
Wellsandt et al. (2017)Study Title: "Risk for Knee Osteoarthritis After Anterior Cruciate Ligament Injury: A Systematic Review of Biological and Functional Risk Factors"Findings: This study found that early RTS (< 9 months) could elevate the risk of osteoarthritis in addition to re-injury. The researchers recommended criteria-based RTS protocols that emphasize functional recovery milestones over fixed timeframes.
Kyritsis et al. (2016)Study Title: "Biomechanical Risk Factors for Secondary ACL Injury: Altered Hip Rotation Patterns in Male and Female Athletes Following ACL Reconstruction"Findings: This study investigated biomechanical risk factors, demonstrating that athletes who passed strength and stability tests after ACLR (often achievable around 9–12 months) had lower re-injury rates.
Ardern et al. (2011)Study Title: "Return to Sport Following ACL Reconstruction Surgery: A Systematic Review and Meta-analysis of the State of Play"Findings: This early meta-analysis reviewed 48 studies and found that less than 50% of athletes returned to their pre-injury levels of sports at the 6-month mark, with better outcomes reported closer to 9–12 months.
These studies collectively support a minimum of 9 months post-ACLR before RTS, underscoring the importance of passing functional benchmarks to lower re-injury risks.
There is value in waiting and allowing that graft to be "integrated" as a part of your body. My advice is wait a minimum of 1 year to be safe. Seek a physical therapist or provider who understands these timelines and work with your coach to train towards getting back to playing. It is a matter of TEAM WORK!
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