Generally 3 weeks. Minimum time is 3 weeks, but there is no maximum limit. As it is a reconstruction, where the ligament is replaced.

The guidelines are to re-assess the knee after 6 weeks. The examining surgeon will check for instability. If the knee is unstable, considering an active person and middle age, reconstruction is the best option. If the knee seems stable, initial physiotherapy can be done for 4-8 weeks. Routine day to day activities won't be affected. Running and other higher activities may be problematic. If so, again surgery has to be considered. It is not an emergency or urgent surgery.

Can start with knee strengtheing exercises  hamstring/quadriceps. Depends on the recovery .Don't rush .