When they turned three last year, Carnoustie twins Ayley and Chloe Hirsch were unable to walk.
On Tuesday both girls were up on their feet as they blew out the candles on their fourth birthday cake.
This time last year, Angus was caught up in the fundraising campaign which eventually exceeded all expectations and saw £175,000 flood in.
The girls, who suffer from cerebral palsy, flew out with parents Averil and Frazer to St Louis Children’s Hospital in Missouri in January for a life-changing operation by renowned surgeon Dr TS Park.
They have amazed everyone with their progress and continue to undergo physio four times a week, while they also work on a treadmill and leg press at their house on Burgh School Close.
Ayley has been running around for months, to the delight of her parents, while Chloe’s hard work has also paid off and she is able to walk in short bursts with sticks.
Averil said: ”They are having a lovely day at nursery celebrating with all their friends. On Sunday, we had 47 kids at the house for a party and everyone had a fantastic time. It was great to see them so happy and having fun.
”Ayley is now running about the house which is something we couldn’t have imagined happening at this time last year.”‘Just fantastic’She added: ”Chloe has also been doing well in her walker but a few weeks ago she surprised all of us at physio by getting up and taking steps with her sticks.
”She can now walk with her sticks in short bursts which brings tears to my eyes.
”This was the target for Chloe and Dr Park didn’t think it would happen until the end of the year. For her to be taking steps with her sticks is a miracle. When I think back to this time last year, neither of the girls could walk and America seemed so far away.
”A year on and I can’t believe how things have turned out for them. It’s just fantastic and it’s thanks to everyone who donated money for the girls’ operation.”
Parents Averil and Frazer’s battle to raise funds for life-changing surgery for their disabled twins captured the public’s imagination when the campaign was launched last February.
Averil and Frazer had set themselves the target of pulling together the £80,000 needed for the surgery but more than £175,000 flooded in from the community.
Averil’s dream is for them to both walk through the school gates together when they start primary school next term.
The girls have also been going to the Brae Riding for the Disabled centre and have joined up with the Fiona Forbes School of Dance in Carnoustie.
They continue to send Dr Park updates of their progress and will return to Missouri in April.