Ethel Sanders from Burntwood died at Queen's Hospital in Burton after suffering from multi organ failure, internal bleeding and blood poisoning due to a two-month delay in receiving surgery and poor care afterwards.
Now the hospital has admitted its mistakes and agreed to pay her family a five-figure sum as compensation.
Her daughters today called on Burton Hospitals NHS Foundation Trust, which runs the hospital, to improve services for the elderly after she suffered months of agony before her death.
The trust has admitted breaching its duty of care to the 85-year-old and has agreed to pay the family an undisclosed five-figure settlement.
Expert evidence commissioned by medical negligence lawyers at Irwin Mitchell found there was a two-month delay in Mrs Sanders having surgery to treat colovescial fistula - a condition which affects the colon and the bladder causing pain and infection.
It also discovered when she did have keyhole surgery to treat the problem, it was performed negligently causing a tear to the ovarian vein.
It was not until the following day that doctors diagnosed her deteriorating condition as being linked to the tear and despite further surgery, it was too late and she died a week later in March 2011.
Mrs Sanders' daughters Linda Ward and Sandra Neal say they remain 'deeply concerned' by standards within the trust and said lessons must be learned.
The trust was placed in special measures by the Care Quality Commission last year as part of a review into death rates at a number of hospitals across the country.
Mrs Ward, aged 61 and from Hednesford, said: "We remain devastated by the loss of our mum - it was extremely difficult to see her suffer like she did. She was in absolute agony for weeks but there seemed to be no hurry to try and help her and we felt completely helpless.
"From start to finish my mum did not receive an acceptable level of care and it is simply not good enough. What makes us so angry is that the trust is clearly not making good enough improvements as it is one of the few hospitals to remain in special measures.
"Mum was vulnerable and elderly and should have been treated with compassion and integrity but we saw none of that and it is heartbreaking to think of how she suffered.
"Action must be taken to improve services for both the elderly, and patients in general to prevent anyone else from going through such a horrific ordeal and to restore faith in the services it provides."
Dr Craig Stenhouse, medical director at the trust, said "This is an extremely sad case and we are truly sorry that the care and treatment given to Mrs Sanders was not of the standard that our patients deserve.
"We completely accept that the quality of care provided was inadequate and we have taken immediate action to make changes."