How long is the rehab acl knee surgery?

3-6 months : Sometimes longer many varibles preop fitness post op goals type of repair fixation device used other injuires your surgeon can tell you best.

Depends...: You may only need formal physical therapy for 2-3 months after acl reconstruction; return to high demand sports/activity generally takes 6 months' minimum; if you have allograft (cadaver graft), i often delay cutting/pivoting/agility/other high demand sports until ~9 months. Talk to your surgeon about his/her acl rehab protocol, your activity goals; time in rehab also depends on how you progress.