do doctors heal?

i was discussing knee surgery with my brother the other day, as he was due to go for a minor arthroscopic surgery to repair the maniscus, or cartilage, in his knee. i have had two similar procedures done to my knee, one of which was a failed reconstruction attempt of the acl of my left knee.
knee surgeries have improved over the years to the point where they are vitually completely successful. the major reason why has been that the procedures are less invasive than they used to be. years ago to do even the most basic exploratory or repair operation meant a major incision and opening of the join it`s self causing major trauma to the join and necessitating months of recovery time. nowadays the tools are so small that even reconstruction can be done through pinhole incisions with little disturbance of the knee capsule allowing for brief recovery times and a better chance recovery.
what i realised in our discussion is that the human body knows how to fix it`s self as long as there isn`t to much damage done by means of surgical procedure. the doctor`s job isn`t so much healing as not damaging.
the human body does the rest. perfectly every time.