A nine-year-old boy has become the first child in the United Kingdom to undergo a pioneering leg-lengthening procedure that specialists say could transform treatment for young patients with limb differences.

Alfie Phillips, from Northampton, was born with fibular hemimelia, a rare congenital condition affecting fewer than one in 40,000 births and resulting in his right leg developing more than an inch shorter than his left.

Surgeons at Alder Hey Children’s Hospital in Liverpool carried out the innovative operation in March 2025, enabling Alfie to gain three centimetres in length and significantly improve his mobility.

The new technique involved implanting a motorised telescopic nail along the surface of Alfie’s femur, the long bone in the thigh.

The device, controlled externally by magnets, was gradually adjusted three times a day for approximately a month, extending the bone by around one millimetre per day.

As the bone ends were gently separated, Alfie’s body naturally generated new bone tissue to fill the gap.

Although similar lengthening nails have been used in adults, placing them inside the bone, the procedure was previously considered unsuitable for children due to the risk of damaging growth plates.

The surface-mounted approach avoids that complication, making internal limb lengthening a viable option for younger patients.

Consultant orthopaedic surgeon Nick Peterson said the technique offers a less painful and more manageable alternative to external fixators, which involve metal frames attached outside the limb.

Before being referred to Alder Hey in 2024, Alfie’s only option would have been an external device.

Alfie spent less than a week in hospital following the surgery and underwent weekly physiotherapy and clinical reviews throughout the six-week lengthening process.

The telescopic nail was removed three to four months after the operation.

His recovery has been described by doctors as remarkable.

Nearly a year on, Alfie says he is "running around as normal" and enjoying activities that were previously more difficult, including basketball, skipping and trampolining.

His mother, Laura Ducker, said he healed exceptionally well and returned to school quickly.

Specialists had measured the initial discrepancy between Alfie’s legs at four centimetres and projected that it could have reached six centimetres by adulthood without intervention.

While he may require further treatment to lengthen his shin bone as he grows, doctors say the early success represents a significant step forward in paediatric orthopaedic care.

The hospital has since performed the same procedure on three other children and other specialist centres across the country are preparing to adopt the technique, raising hopes that the approach will replace more invasive traditional methods for suitable young patients.