A bone operation performed on an elderly cancer patient after she fell out of bed was justified although it now appeared it might have hastened her death, an expert witness told an inquest yesterday. Doctors who operated on Chan Wun-sik's broken leg at Princess Margaret Hospital did not know that cancer cells had spread to her bones, Frankie Leung Ka-li told the Coroner's Court. So they did not take into account the possibility of complications in which clots formed in blood vessels in the lungs and other parts of the body, said Dr Leung, honorary clinical assistant professor at the University of Hong Kong's department of orthopaedics and traumatology. Chan, 74, had the operation on July 20 after her fall in the early hours of the previous day. She died the next morning after developing acute breathing difficulties, low blood pressure and abdominal pain. She had been due for an examination of her tumours on July 20, but it was called off because of the bone operation. An autopsy report read out earlier said the direct cause of death was medullary thyroid cancer and clots in her blood vessels. The cancer was found to have spread to other parts of the body including a thigh bone. Without the fall and operation, Dr Leung estimated, Chan might have had only a few more weeks to live. The inquest continues today.