Bubbles show promise for bone repair

Southampton researchers are developing a new way of healing broken bones that avoids the need for surgery.

Bone fractures are a significant public health problem - costing the UK around £2 billion each year.

A new study has shown that tiny bubbles may be used to transport drugs to the site of a broken bone. This understanding could lead to a new way of treating fractures that fail to heal on their own.

Professor Nick Evans from the University of Southampton led the study with colleagues from the University of Oxford. They recruited patients from University Hospital Southampton (UHS).

Non-healing fractures

One in three people will break a bone in their lifetime.

Most will get better on their own – but every fracture carries the risk of failing to heal properly. This complication, known as a non-union, occurs in between 5% and 10% of cases.

Breaks of this kind can cause severe pain and disability, and often lead to surgery.

Alternative to surgery

This study involved eight patients with a broken upper arm.

They each had microbubbles injected into their bloodstream. These are very small bubbles of gas that are routinely used in ultrasound imaging.

The results show that microbubbles can be successfully carried to the site of a fracture. A pulse from an ultrasound device may then be used to pop the bubbles open, releasing a drug at the target location.

“Our early results are extremely promising”, said Prof Evans, a Professor of Bioengineering.

“What we’ve shown is that microbubbles get to bone fractures and might be used to deliver drugs to the right place at the right time.

“The method could offer a less invasive alternative to surgery for non-union fractures in the future.”

‘Huge’ potential

The economic cost of bone fractures is expected to increase as the number of older people in the UK grows.

This means there is an urgent need for new non-invasive and cost-effective treatments.

Simon Tilley, a Consultant Orthopaedic Surgeon at UHS who was involved in the study, said:

“The concept of using microbubbles to aid bone fracture healing is huge.

“Non-union fractures are devastating for individuals and represent an enormous cost to society.

“Reducing the amount of time it takes to heal these fractures would have major benefits for patients and hospitals alike.”

The next stage of the research is to find out how many microbubbles reach the fracture site, and if this amount changes based on the time that’s passed since the bone was broken. The team will explore this in a larger study set to open in Southampton this summer.

They are also testing new microbubble formulations in the lab to see what other drugs they could carry.