###Human: I have swelling in knee after four months of ACL meniscus surgery. Why? ###Assistant: Hello. The knee swelling can even persist till six months after surgery, the more physiotherapy you do and the earlier you achieve full range of movements of the knee, the better it is and faster the swelling will reduce. Weakness can be overcome by physiotherapy again to strengthen your quadriceps and hamstring muscles. Running will depend on your physical follow up with your doctor and also will depend on your physio. Ideally, by now you should have started running but your physio and doctor will decide that as every case is different. ACL post-surgery rehabilitation.