Ultrasound 'boosts fracture healing'

An ultrasound device “helps bones heal faster and stronger,” reported The Daily Telegraph.

The news is based on a trial that investigated whether a device emitting low-intensity pulsed ultrasound (LIPUS) could improve bone repair in patients whose shin bone fractures had healed slowly during the four months since their injury.

The trial gave 101 slow-healing patients either a genuine LIPUS treatment or an inactive sham treatment over 16 weeks. The LIPUS device was found to increase bone mineral density by 34% more than the sham device, and 65% of the LIPUS-treatment group were considered by a doctor to be healed compared to 46% of the sham-treatment participants.

While there was a drop-out rate of around 10%, the use of the device looks promising as it is a non-invasive treatment and no side effects were reported. Overall, this preliminary trial suggests that the treatment may be of some benefit to patients with delayed fracture healing.

Where did the story come from?

The study was carried out by researchers from University Hospital Marburg and the University of Ulm in Germany. It was funded by Smith and Nephew, the manufacturers of the device used in this study. The study was published in the peer-reviewed medical journal BMC Musculoskeletal Disorders .

The research was well reported by The Daily Telegraph.

What kind of research was this?

This was a randomised controlled trial that assessed whether low-intensity pulsed ultra sound (LIPUS) would increase bone healing compared with a sham treatment. The researchers were interested in whether the treatment would help people who had shown a slow rate of healing four months after their injury.

The researchers say that LIPUS has been shown to enhance healing in fresh fractures, and that some non-controlled trials suggest that LIPUS may help promote healing in older fractures that have failed to heal. However, they said no randomised controlled trial has been carried out among patients who had delayed fracture healing.

The manufacturers of the device suggest that the LIPUS device can perform several different roles in bone healing. They say that immediately after a break it can remove debris and bacteria from the site of the wound, while in later healing stages it can stimulate the bone marrow to produce immature bone cells and cartilage cells. The manufacturers say that during latter-stage healing (the period examine in this study), the device stimulates the membrane around the bone to seal. This allowed immature bone cells to collect and grow.

What did the research involve?

The research was carried out in six hospitals in Germany. The study recruited adults who had a fracture to their tibia (shin bone) but had displayed inadequate healing at least 16 weeks after their injury. The study did not include patients who were pregnant, had infected wounds, had excessive malalignment of their bone following the fracture, or had received an operation at the fracture site within 16 weeks of enrolment.

In total, 101 subjects between 14 and 70 years old were recruited and randomly allocated to treatment with either the active LIPUS device (51 people) or an inactive ‘sham’ LIPUS device (50 people). The device was the Exogen 2000/2000+, which is manufactured by Smith and Nephew in Germany.

The participants were instructed to use the device for 20 minutes a day for 16 weeks. All of the devices recorded the usage time per day as a means of assessing whether the participants were complying with the study protocol.

Computed tomography (CT) scanning was used to assess bone mineral density (BMD) and the gap at the fracture site. BMD was assessed at three regions of interest: the fracture site, 2-3 mm either side of the fracture site, and a healthy reference area. These measurements were taken before treatment and after the 16-week treatment course. Radiographs were also taken at one, two and three months. These were shown to doctors who judged the healing status (healed/not healed) of each subject.

What were the basic results?

Out of 101 participants who started the study, 84 completed it. Twelve out of the 50 participants who received sham treatment dropped out (24%), and five out of 51 of the LIPUS treated patients dropped out (9.8%). Overall, compliance with the treatment regimen was good. The median total time of device usage was 2,040 minutes out of a possible 2,240 minutes (91%).

In their statistical analysis the researchers took into account the potential bias of patients who had dropped out. The improvement in BMD was 1.34 (90% CI, 1.14 to 1.57) times greater for LIPUS-treated participants compared with the sham controls (p=0.002). The LIPUS-treated participants also had a greater reduction in the gap between their bone at the fracture site compared to the controls over the 16-week period (p=0.014).

At completion of the 16-week treatment period, 65% of LIPUS and 46% of sham-treated participants were considered by a doctor to be healed (p=0.07). The LIPUS device did not cause any side effects.

How did the researchers interpret the results?

The researchers said that under normal clinical circumstances, approximately 4.4% of patients with shin bone fractures will have delays in bone healing. Surgery and bone grafts may be necessary in these patients. The researchers said that their research has extended the positive findings that LIPUS treatment can help healing in fresh fractures by showing that it benefits patients whose fractures have taken longer to heal.

Conclusion

This was a well-conducted randomised controlled trial, which showed that use of LIPUS improved the healing process by 34% compared to a control treatment.

As the device was used by the patients at home, a good aspect of the study design was that it recorded the amount of time patients used the device to assess whether they followed the study protocol. However, compliance with the device and adherence to the treatment instructions may be different when used by patients outside of the study setting. Also, 16% of the participants dropped out of the study, and their reasons for dropping out were not presented.

As more patients had dropped out of the sham control group than the LIPUS group, the researchers used statistical modelling to adjust for potential bias this may have caused to their results. However, details of how this was done were not explicit.

Overall, this preliminary study suggests that this non-invasive treatment appears to be of some benefit to patients who have delayed fracture healing.