As an infant, Anna Rose O’Sullivan had pigeon toes – now she is a pirouetting princess. Caroline Phillips reports

When Anna Rose O’Sullivan was 10 months old, her mother, Jacinta, feared that her daughter might never walk properly. The infant’s feet turned inwards and she walked on her ankles. Jacinta’s mind was filled with visions of splints, braces and corrective shoes. In severe cases of pigeon toes, she discovered later, remedial surgery is required.

This weekend, Anna Rose, now aged 10, will dance the lead role in the London Children’s Ballet revival of A Little Princess – standing on her tip-toes and turning out her feet perfectly for the demanding part of Sara Crewe, a little girl left orphaned, penniless and at the mercy of the wicked Miss Minchin. She dances for most of the 90-minute performance.

“One week, we rehearsed for five hours every day,” says Anna Rose. She has also just taken over as Cosette in the long-running musical Les Miserables.

“It’s quite a big part,” says Anna Rose, proudly.

The sitting room of the O’Sullivans’ modern Uxbridge home is filled with silver ballet trophies.

“Upstairs,” says Anna Rose, “I have 24 ballet medals.”

Pigeon toes – also called in-toeing – occurs when the front of the foot is turned to face the other foot, and – like bowlegs, flat feet or knock-knees – is a common condition in children.

“Pigeon toes is a general term. It’s nearly as unspecific as `backache’,” explains John Strachan, who worked as orthopaedic surgeon to the Royal Ballet for 31 years. “It usually has postural or anatomical roots. For example, if the hip isn’t positioned correctly, the foot will turn in to compensate. The toes themselves aren’t usually deformed. It’s just a description of gait and the position of the feet.”

Rarely, the condition is caused by a twist in the thigh or shin bone, or an abnormal curvature of the foot (metatarsus adductus). In most cases of in-toeing, the problem corrects itself naturally by the time the child reaches school age – which was the case with Anna Rose. As muscles strengthen and the bones grow, they straighten out.

Nobody knows for sure why the condition occurs. One theory is that it is the result of crowding in the uterus. When a baby’s hips, shins or feet are squashed in utero, they may turn in as they develop. This is more likely if the mother is carrying her first child or twins, or has reduced amniotic fluid.

“Anna Rose was a big baby – nine and a half pounds,” says Jacinta.

Generally, in-toeing doesn’t affect athletic ability. But, in serious cases, it can cause a child to trip and fall. In the past, special shoes, splints and leg braces were used, but they are rarely prescribed now, as they have had little effect in speeding up the natural, slow improvement.

Typically, in-toeing appears between the age of a year and 18 months, when the infant begins to stand. Jacinta noticed the problem when Anna Rose started to walk.

“Two of her adult relations suffer from it, on both sides of the family,” she says. “So I was terrified it was going to be a permanent condition.”

“If there’s an anatomical problem, it could be genetically linked, but this is rare,” says Strachan. “For Anna Rose, it sounds more like a coincidence.”

Jacinta took her daughter to the family doctor. There, her fears were dispelled. Anna Rose’s in-toeing wasn’t severe.

“The doctor thought her knee turned in, making her walk like that,” says Jacinta. “He said it might correct itself when she came out of nappies – because wearing them distorts the way you stand. Then, I worried about it cosmetically. It was very unsightly.”

The GP suggested that Anna Rose should wear sturdy boots with ankle support and an arch to strengthen her insteps. He also recommended regular foot massages and advised Jacinta to take her to ballet classes as soon as possible.

“Every time I changed her nappies, I’d massage her feet from inside ankle to toe for a few minutes,” says Jacinta.

Just before Anna Rose’s third birthday, Jacinta started taking her to ballet twice a week.

“Standing in an out position helps strengthen the muscles and makes your feet and legs strong,” says Strachan. “Ballet helps as long as there’s no underlying anatomical problem – which is generally the case. It’s important because the child is doing something enjoyable, but learning to walk with the feet facing out.”

Earlier this year, Jacinta took Anna Rose to a ballet physiotherapist. Ever greater dancing demands are being made of her and Jacinta wanted reassurance that her daughter had no anatomical problems that might one day prevent her from dancing.

The physiotherapist stretched and manipulated her feet at length, then declared her body to be perfect for ballet.

“More than anything,” says Anna Rose, “I want to be a prima ballerina with the Royal Ballet when I grow up.”

A Little Princess is at the Peacock Theatre, Sadler’s Wells from tonight until Sunday.