Few teens would be excited at the prospect of major surgery followed by months of intensive physiotherapy, but after hobbling kilometres to school for more than a decade, Sonia Paua is one.

"It's a dream come true and I can't wait", says the 18-year-old from Papua New Guinea, who will undergo leg-lengthening surgery at Richmond's Epworth hospital on February 1. 

"Soon I will be walking straight, without a crutch, and I won't be embarrassed any more. My family will be really happy and proud of me when I arrive home, standing up straight".

Sonia - who has one leg significantly shorter than the other as a result of a childhood bone infection - says her life will be forever changed by the surgery, which will see Melbourne orthopaedic surgeon Minoo Patel add centimetres to her left leg. 

After the surgery, she will endure months of rehabilitation before turning home to her family in Port Moresby.

The long recovery doesn't faze her because she's familiar with pain and has determination in spades.

And opposed to the pain she has known since she contracted osteomyelitis while living in the PNG highlands at age seven, any pain post-surgery will be positive. 

The agonisingly long and slow limp to her school in PNG would take up to an hour each morning, as she needed to stop and rest so frequently, she says. 

"I'm not really smart, I just try hard," Sonia says. 

"I want to go to university and become a doctor who looks after bones, so I can help other people like me".

Sonia says she is overwhelmed by the generosity of the Children First Foundation (CFF), which paid for her to travel to Australia for the surgery, and is caring for her at its Kilmore retreat.

The foundation will also cover Sonia's considerable physiotherapy costs and accommodate and look after her for months following her surgery, says CFF chief executive Elizabeth Lodge. 

"We manage the entire process", she says.

The surgery itself - which will see a rod inserted in Sonia's leg and take up to four hours - will be performed, for free, by Professor Patel and his Epworth team. 

Sonia's post-surgical stay at the Epworth hospital in Richmond will also be provided at no cost to her family. 

"People ask me why I do it. I do it because it's interesting work but it also gives you a thrill you can't explain to make such a difference to someone's life" Professor Patel says.

Sonia's deformity is the result of surgeries in PNG when she was younger to remove the disease bone and related scarring and skin contracture, he says. 

"Unfortunately, this all happened while she was still growing, so her limb is deformed both at the bone and the joint, and it is shorter as well."

X-rays of Sonia's leg show how her femur has become "bent and sguiggly" and her knee deformed, due to the childhood infection, Professor Patel says.

At 18, nearly 19, Sonia is now the ideal age for corrective, limb-lengthening surgery, Professor Patel says.

"When you are a bit older, these things are easier to do", he says of the complex procedure. 

For Sonia, who thought the day would never come when she would "walk straight up" again, the gratitude she feels for CFF, the Epworth and the medical team giving up their time for free to help her live a normal life and realise her dream of becoming a doctor, is at times overwhelming.

"Sometimes, I still can't believe it" she says.

"I can't believe I am going to be fixed".

Epworth HealthCare will celebrate its centenary on February 27 this year. 

Picture courtesy: Mark Stewart

News story: mandy.squires@news.com.au