King Juan Carlos' knee op 'successful'

Ccording to the La Moraleja University Hospital, the Rex Emeritus had to have another knee replacement – the prothesis fitted to his right knee in 2011 has already worn out.

Surgery took just an hour and a half and was 'very successful', said a press release from the hospital.

Following the operation on Saturday morning, King Juan Carlos I – who abdicated in favour of his son in the summer of 2014 – was in intensive care until around Sunday lunchtime for post-op observation, mainly due to his age: he turned 80 on January 5 this year.

As soon as he was on a ward, his son King Felipe IV and daughter-in-law Queen Letizia visited him with their two daughters, Leonor, 12 and Sofía, who will be 11 next month.

They were accompanied by Juan Carlos I's wife Sofía, who retains her title of Queen even though her husband is no longer on the throne.

Reporters were eager to see how the family behaved as they arrived for their visit, since a spat between the two Queens outside Palma de Mallorca cathedral, which seemed to be linked to the children posing for photographs, was caught on video and has gone viral.

Media speculation about ruptured relations between the two women is rife, although Queen Sofía and Queen Letizia have always got along very well – in fact, HRH Letizia named her youngest daughter after her mother-in-law as a token of appreciation for her support when she first became Princess of Asturias after her wedding to the then Prince Felipe.

And photographs of the family entering the clinic show the two Queens walking closely together, smiling at each other.

King Juan Carlos' elder daughter, the Infanta Elena, was also photographed visiting him in hospital and waved to reporters as she left.

The ex-monarch has had 15 surgical operations over the course of his life, of which nine of them were between 2010 and 2013.

He had managed to avoid going under knife for five years until this weekend.