When you have an ACL reconstruction, a new ligament is created and fixated in your knee. The ACL then requires an adequate amount of time to heal for it to withstand stress from any activity. If the new ACL graft is overly stressed before proper healing, the fixation and new ACL can loosen and fail.
Exactly how long the ACL graft takes to heal is open to debate. Graft fixation is crucial in the first 6-12 weeks when the new ACL graft to bone healing occurs. The type of graft used and surgical technique also affects this time. Additional procedures performed along with the ACL reconstruction, such as meniscus repairs must also be considered with respect to recovery time.
Overly aggressive rehabilitation, returning to stressful physical activity too soon, or stopping your therapy before your muscles have had a chance to regain their strength and motor control for coordination and knee joint protection can all lead to re-injury or ACL graft failure.
One of the most well know examples of a post-op ACL injury occurred when former NFL wide receiver Jerry Rice returned to action only 14 weeks after his ACL reconstruction. Unfortunately even one of the NFL’s greatest wide receivers of all-time could not beat the ACL recovery timeline, and he fractured his kneecap in his first game back after landing on his feet from a touchdown catch.
It is important to understand that some sports, jobs, and activities place higher demands and stress on the knee, and more healing may be necessary prior to returning to these activities. Most rehabilitation specialists agree that a minimum of 6 months is needed before returning to competitive sports. Because of the potential risk of re-injury, many recommend waiting at least 7 to 9 months, especially for more demanding activities like skiing and contact sports.
It is crucial to understand that ACL rehabilitation is a long process, but is not solely an issue of time. It involves a skilled progression from one phase of rehabilitation to the next, and you must reach certain benchmarks to indicate it is safe to advance to the next level. That is why working with a skilled physical therapist for the entire duration of your rehabilitation is crucial for long-term success after ACL surgery.