###Human: I am unable to exercise after ACL surgery. Will it cause any complication? ###Assistant: Hi. Usually, it takes 1 to 2 months for recovery from surgery and 3 to 4 months for muscles to regain their usual strength after ACL surgery. Since you cannot exercise it means that your muscles have not reached their optimal strength till now. Arthrofibrosis is a common complication after such surgery that can prevent you from exercising. But to know the exact cause, I would suggest you have MRI or bone scan of the knee joint to know the exact cause. Also, I would advise you to have physiotherapy sessions.