A woman died in hospital 10 days after a knee operation, an inquest heard.

Pamela Davis, 69, of Harlequin Way, Banbury, suffered a blot clot on the lungs caused by deep vein throm- bosis. She died at the Horton Hospital, Banbury, on October 21.

Mrs Davis had been admitted to the Horton for a replacement knee operation, carried out on October 11.

Her daughter, Lynn Houghton, said: "One day she would be fine and the next she would be breathless."

Bijan Shafighian, a consultant orthopaedic surgeon, who dealt with Mrs Davis's previous knee operations, said: "After the second operation to her right knee, she was admitted to hospital with suspected deep vein thrombosis in 1994, but test results were never able to confirm the diagnosis."

In view of her past medical history, Mrs Davis was given a drug to help stop blood clots forming after her operation in October.

Regular tests and x-rays were unable to establish what was causing her to feel out of breath, and a second opinion from a colleague confirmed Mr Shafighian's view that Mrs Davis did not have a blood clot on her lungs.

Mr Shafighian said: "None of Mrs Davis's signs and symptoms matched those of someone who has deep vein thrombosis. She had no swelling or tenderness in her legs and no tempera- ture."

Consultant pathologist Dr Nicolas Mahy said it was not unknown for people to die of suspected heart attacks, when they had died from a blood clot on the lungs without any warning signs.

Coroner Nicholas Gardiner recorded a verdict of death by misadventure. He said undergoing surgery was inherently risky, despite all the precautions taken in Mrs Davis's case.