Gwendolyn Marshall, of Rylstone Drive, Heysham, died at age 77 at Royal Lancaster Infirmary on Sunday, January 9, after fracturing her arm when she fell at home.
Despite Gwendolyn seeming to recover from the injury, she required a routine operation a few weeks later.
That is when Mr Shyam Kumar, a consultant orthopaedic surgeon, discovered a broken bone in her arm had moved and ruptured a main artery, causing her death.
Her death was accidental and caused by a mixture of frailty, type two diabetes, hypertension, multiple organ failure and fracture injury, Preston Coroner’s Court ruled on Thursday.
Mr Kumar said: "The family’s traumatised; I’m still traumatised. Some cases we always remember.”
Commenting on the factors causing her death, he added: "They were extremely unusual circumstances. For something to have moved the fracture that much a few weeks down the line is very unusual. We tried to find out if something similar has happened before, and found three reported cases all over the world."
Gwendolyn, who lived alone and was cared for by her children, was admitted to hospital on December 7 after losing her footing and collapsing while reaching to turn off the fire.
The grandma, who was mum to Joanne, Mary, Leona and Kevin, was treated alternatively with a hanging cast, brace and a sling for her fracture, with an X-ray on December 14 showing that swelling in her arm had decreased.
But Leona O’Farrell, Gwendolyn’s daughter, said her mum was in “great pain" when she arrived to help care for the pensioner on Christmas Eve.
She added: “I gave her painkillers every four hours but she was practically begging me for more.”
Her sister Mary O’Farrell said: “Mum was delirious, wandering around at 4am, and tried to take her sling off.”
Meanwhile, Gwendolyn’s third daughter, Joanne Moynihan, added: “That much pain must have been torment.”
Their mum returned to hospital on January 6 as the fracture had trapped a nerve, leading to an uncommon complication called wrist drop. This disorder refers to the inability to actively extend the hand at the wrist.
The grandma was wheeled into surgery the next morning, which is when Mr Kumar realised a small piece of her bone had pierced an artery, causing severe bleeding. A vascular surgeon rushed over from Preston to remove the splinter, repair the artery and control the bleeding, before carrying out a bypass operation.
Despite surviving it, Gwendolyn died the following day.
Commenting on the patient's frailty, Mr Kumar said: "It’s a big assault on the body for it to be under general anaesthetic for so long. She lost a lot of blood. At that age, any loss of blood is an assault to the system.”
Concluding, area coroner Mr Richard Taylor said: “This is such an unusual set of circumstances, outside of anyone’s experience. [Gwendolyn’s fracture] is an innocent thing that doctors see day-in day-out. Something happened to interfere with it, so it had been displaced, [causing] artery damage. They tried everything to save her but once that damage was done, sadly it was the start of the end. Without that fall, we wouldn’t be sitting here today.”