An 81-year-old woman who spent more than two-and-a-half years in agony after surgeons failed to identify that she needed a new hip - and then had to pick up the bill - says she is “appalled” at the way she has been treated.

Tessa Alexander, of Bricket Wood, had back surgery at Watford General Hospital in November 2011. However, once she had recovered she noticed shooting pains in her legs.

Doctors then began routine spinal injections and put Tessa on a “cocktail of painkillers”, including morphine, to deal with what they thought was fall-out from the back operation.

It was only when Tessa’s dentist suggested Pilates to deal with the pain in her legs more than two years later that she suspected that the cause of her pain might lay elsewhere.

She said: “Within five minutes [the Pilates instructor] said: ‘There’s nothing wrong with your back; you need a new hip.’ So I went to the doctor and said I needed an X-ray on my hip.

“I had the X-ray and the registrar said: ‘I’ve got your X-ray here. You’ve got a terrible hip and if you’re not careful, the other one will go.’

“So the back was correct, but they totally missed the hip.”

Tessa was then told she would need to wait a further 18 weeks for surgery, despite having complained of the symptoms for two-and-a-half years.

She said: “I told them that it hadn’t only just been diagnosed. It had been misdiagnosed all these years.”

According to Tessa, staff then failed to offer her access to the now-defunct Choose-and-Book service, which would have allowed her to book her own appointment and have the surgery within a few weeks.

So instead of spending another 18 weeks in pain, Tessa decided to have the hip operation done privately - at a cost of £11,000 - in the hope that that the NHS would reimburse part, if not all, of the money for failing to identify the problem for such a long period of time.

Tessa said: “It’s a lot of money. It’s my children’s inheritance. But they didn’t want to know.”

Having devoted years of voluntary work to Watford General Hospital, working on the PPI forum (patient and public involvement) and later in the PALS office (patient advice and liaison services), which she had to give up because of the pain in her legs, Tessa hoped that she might have been better supported.

However, she said: “I worked very, very hard for the hospital and I just think they’ve treated me shabbily.”

Mike van der Watt, medical director at West Herts NHS Trust, said that the Choose-and-Book system would have been available to Tessa via her GP, adding that: “This is not determined by the hospital.”

He said: “Mrs Alexander requested that she have her hip replacement procedure within two weeks.

“Unfortunately there were other patients waiting in similar or more pressing circumstances, and this was impossible.

“Mrs Alexander decided to have the operation privately. The NHS cannot reimburse patients in these cases.”

However Tessa said that the allegations that she had demanded the surgery be done within two weeks were “utter rubbish”.

She said: “I didn’t have it done within two weeks anyway.”

Tessa has since lodged a complaint with the Health Service Ombudsman.