6 weeks to 6 months. This varies on the type of surgery and severity of associated knee injuries. Initially, physical therapy is critical to help regain full range of motion (2-6 weeks). Later, therapy is imperative for regaining strength, flexibility and agility. This period depends on the type of activity you desire to return to and can vary from 6 weeks to 6 months. In general, therapy should last several months.
3 months is routine. Not all ACL injuries/reconstructions are the same. I routinely prescribe 12 wks of formal ptx after ACL reconstruction. Incremental reevaluations @ 1, 6, and 12 weeks allow this standard timeline of therapy to be adjusted to best suit the needs of each patient with a goal to reach maximal functional recovery for all activities of daily living by 3 months. A walk to jog program can begin @ 12 wks.