World 400m hurdles champion Jana Pittman has been given a 60 per cent chance of competing at the Olympic Games after undergoing knee surgery.

"We're back in the mix," Pittman's coach Phil King said.

"It was nowhere near as bad as first interpreted."

Pittman flew to London for a second medical opinion after she tore cartilage in her right knee during the warm-up for her final pre-Olympic race in Zurich on Friday night.

King said the London surgeon discovered a lot of the damage displayed in a MRI scan was from past wear and the tear to her lateral meniscus was only slight.

Pittman, who was given a general anaesthetic, had surgery on the knee in London on Monday when the surgeon shaved the tear out of the cartilage.

"The news is all very good," King said.

"The surgeon quoted there was a 60 per cent chance of running in Athens.

"We're over the moon, I think it's due justice that Jana has a chance of going at it."

Pittman will remain in hospital in London for another day before heading to Italy to join the Australian track and field team in Varese, in the north of the country.

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