Volker Musahl - one of the doctors who operated Manchester United striker Zlatan Ibrahimovic - has dismissed claims from the attacker's agent Mino Raiola that they want the 35-year-old to return to Pittsburgh after his career so they can research his knee.

Ibrahimovic required surgery after sustaining a cruciate ligament injury during United's 2-1 win over Anderlecht in the Europa League in April.

Following the surgery Raiola claimed the doctors were so impressed with the condition of the ex-Sweden international's knee that they wanted to study it at some point in the future.

However, Musahl has now downplayed such suggestions.

"It was a routine surgery. There were no complications," the German doctor told Die Welt.

"Zlatan has a very good bone structure and his knee is absolutely in a good condition. But it is a bit of an exaggeration to say it will be a research object."

Ibrahimovic faces a lengthy spell on the sidelines as he recovers from his operation, but Musahl was unable to clarify how long the former Paris Saint-Germain man will be out of action.

"I cannot give an accurate prediction as to how long his recovery will last," he added.

"Our goal is always to help the athletes make a quick and safe comeback.

"Ibrahimovic was quite pleased with the way the surgery went. He is very strong."