With hindsight, Mr Picone says his injury was "the best thing that ever happened" to him. It made him realise his own limitations and taught him to look after himself better.
Like many young dancers, he was pushing himself, or being pushed, even when exhausted.
"I was a young principal coming up, and we have to do a lot of performances," he said yesterday. "When you are young, you don't concentrate: you just dance with talent, your possibility. But if you don't concentrate you do steps wrong and you get injured."
Ballet staff were also to blame, he said. "They have to care that if they throw us on stage every time there is a performance, we'll get injured. They do force people a little to dance. Because we're doing a lot of performances [177 a year in the English National Ballet's case], people get tired - but they still must do the performance."
Mr Picone no longer spends every spare moment practising his steps. "I've realised that ballet isn't everything in this world," he said. "For ballet to be one's sole obsession isn't good. If you don't enjoy life, it's bad for your health."
He has radically altered his eating habits, too. He used to skip meals frequently and sometimes didn't eat all day. "Now I am eating better and sleeping better, which means my muscles can relax more."
He became depressed when he was ill. "If I went to watch a performance, I would get really depressed because I couldn't dance and the leg would be painful. That would be the worst," he said.
But unlike many dancers, Mr Picone was fortunate in one respect. He did not have to pay a penny towards his treatment.