Lebron probably takes HGH, you'd notice the difference last year when he was less athletic and less cut up then suddenly returned to his previous form. He probably got off the shyt when he heard the NBA was testing for HGH and didn't want to get caught, then he was probably told some shyt from trainers or some NBA heads and decided to get back on it.
However, if you just look at him you can see he has those heart of Nigeria genetics. So because of that he'd be more resilient, stronger,more athletic etc.
Injuries are so common that I don't think any drug can protect you from them if you cut too hard at the wrong angle or slip or whatever, so I think Lebron is just naturally really sturdy with great body control.