Dr Freddie Fu, who operated on Zlatan Ibrahimovic says the veteran striker can play at the top for many years.
Ibrahimovic had surgery done on his knee in the United States and faces a long time of rehabilitation, casting doubt on his future at United, with his contract nearing an end.
However, the experienced orthopaedic surgeon is positive the former PSG man has what it takes to compete at the top level.
Fu said: “I can’t discuss too many details, I don’t want to get in trouble with Manchester United.
“But I can tell you he’s in superb shape in all things.
“Healthy morphology, the quality of the bone and muscle, everything is as good as you can possibly see.
“He’s one of the top athletes I’ve ever touched, he is in superb shape.
“He can still play for many years.”