On how active you are and how much was done during surgery.
For a routine knee scope i typically allow my patients back to work in 3-4 days if they have a sedentary job. Otherwise, most people can start getting back to work at 2-3 weeks depending on their job. Strengthening of the quadriceps muscle is key as this shuts down with knee surgery of any kind. Most people are near full by 4 weeks.