Trainer Chris Waller has revealed champion mare Winx has undergone arthroscopic surgery to remove a small bone chip from a fetlock since her Doncaster win.

At a teleconference on Thursday, Racing NSW stewards interviewed Waller about the treatment, mindful of the public interest in the mare.

They considered veterinary reports from the stable and Racing NSW chief vet Craig Suann before deciding Waller had been compliant with the rule.

Waller confirmed the time line of events.

After her win in the Doncaster on April 2, Waller opted not to run Winx in the Queen Elizabeth concerned she had had a demanding run and did not want to run her again on a testing track.

As a matter of routine on April 6, Waller requested a complete veterinary examination be performed on Winx before she went for a spell.

The veterinary examination, which included endoscopy, scans and radiographs revealed a small bone chip to the near fore fetlock.

The bone chip was removed arthroscopically on April 11.

Waller told stewards Winx had been cleared by the stable vet to run in a barrier trial on July 29 and in his opinion had no effects from the procedure.