Caron Davis said that she was introducing her character, Dinah, to the audience at a show in March 1994, when the toe-stop on her right skate failed to brake and her legs flew up in the air before she ended up on her backside.
"I was in shock but I carried on singing," she told Judge Christopher Hordern QC. "I was so embarrassed because I never fall over. I was one of the strongest skaters in the show, but I couldn't do anything to keep my balance. The adrenalin was still pumping, the muscles still warm, and I carried on with the show."
Ms Davis, 31, of Ruislip, west London, described how damage to ligaments in her lower back meant she had to retrain as a reflexologist. "I miss my career as a dancer - this is what I've been doing since I was three," she said.
Ms Davis, whose stage name was Caron Cardelle, is suing the Really Useful Theatre Company Ltd, which manages the Andrew Lloyd-Webber musical at the Apollo Victoria theatre, claiming it was negligent in not doing more to keep the stage clean.
The company denies liability and claims the accident was caused by her own lack of attention or lack of skill.
Ms Davis told the court that after her fall she discovered fluff on her toe-stop which, she said, was either blown on to the stage by the air-conditioning or came from new carpet in the front of house.
Her counsel, Howard Lederman, said the show in which she was injured was briefly stopped shortly afterwards for the stage to be swept and treated with a special cleaner. The stage manager's report for the performance showed that various cast members complained that the stage was slippery. A report from another performance four months later said it was like an "ice-rink".
The case continues.