Real Madrid's Sergio Ramos undergoes knee surgery

Real Madrid captain Sergio Ramos underwent surgery for a knee injury that has sidelined the defender since last month, the La Liga club said on Saturday.

Ramos, 34, has not played since their Spanish Super Cup loss to Athletic Bilbao last month and though he returned to training earlier this week, he was forced to go under the knife.

"Our captain Sergio Ramos has been successfully operated on today for an injury to the internal meniscus of his left knee," the club said in a statement. "Ramos will begin the recovery process in the next few days."

The club did not say how long Ramos would be out of action, but Spanish media said he would be ruled out for six to 10 weeks.

That would mean he misses their Champions League last-16 tie against Atalanta and possibly most of the rest of the La Liga campaign, with defending champions Real sitting third, 10 points behind city rivals and leaders Atletico Madrid.

The Spain international is yet to resolve his future with Real, with less than five months left on his contract with the club where he has spent the last 16 years.