A YOUNG girl is travelling to Switzerland for pioneering surgery after her crippling condition baffled UK experts.

Milly Maddison, four, whose thigh bone is held in place only by muscle, will have a new hip built entirely of pig bone.

Her condition is so rare that medics have named it "Milly's thing".

Milly, a reception pupil at St John Bosco RC Primary, in Sunderland, has a shrunken pelvis and was born without a left hip socket -a condition never before seen by doctors in the UK.

Last week, her mother, Karen, was told that her local NHS trust had agreed to fund the intricate surgery.

The 41-year-old, of Town End Farm, Sunderland, said: "Through her life, she will have to keep having her hip replaced, and because she does not have the balance.

"Every time she falls over, she could shatter what little bit of the hip she has left."

She first noticed there was something wrong with her daughter when she saw a dimple at the base of Milly's spine.

She said: "There was a lot of muscle wastage, which meant she had no left buttock. By nine months, she was getting on her feet, but favoured her right leg and was using it to compensate."

She was sent by perplexed medics at Sunderland Royal Hospital to a hospital in Sheffield.

Her mother said: "I asked what they called it, so I could find out some more, but apparently it's very rare, so rare they have just called it 'Milly's thing'.

"I was told to see both the hip and pelvis like that is virtually unheard of."

Milly underwent five hours of surgery that left her in a full body cast for two months, but her breakthrough came when an orthopaedic expert in Berne, Switzerland, agreed to help.

Health bosses have now given the go-ahead to fund the procedure and pay for travel and accommodation.