Patient: Hello, doctor! I have a question for you, my mother is 52 years old, she just had ACL reconstruction surgery in August, using allograft tendon, now it has been almost four months, the pain is very strong when exercising, and her leg can only be bent to 90 degrees. I want to ask how to exercise to return to normal, do I need to do physiotherapy? If I do physical therapy, will it hurt my leg? Doctor: You should exercise after surgery. On the second day, the leg should be lifted slowly and progressively until it is ready for weight-bearing activities. Do not exercise if there is redness or swelling. Physical therapy is needed.