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Pulsed Ultrasound Doesn't Promote Bone Healing or Lessen Pain

March 3, 2017
Contrary to popular belief, results of a large, systematic review suggest that low-intensity pulsed ultrasound does not hasten bone fracture healing, support function improvements, or reduce pain.

Interview with Stefan Schandelmaier, MD

Low-intensity pulsed ultrasound (LIPUS) long has been considered an adjunct treatment for patients recovering from fresh bone fractures. However, researchers now believe LIPUS offers no beneficial effect on patient outcomes, including functional recovery and pain reduction, and may not even have an effect on radiographic bone healing.1

Many past studies using LIPUS have been lacking in quality. Now, with new trial evidence emerging, this systematic review, published in the British Medicine Journal, is the latest examination of the efficacy of LIPUS, according to Stefan Schandelmaier, MD, who is at the Department of Clinical Epidemiology and Biostatistics, McMaster University, Ontario, Canada.1

“Previous reviews that assessed the quality of studies came to similar conclusions, regarding study limitations, such as small sample size, poor reporting, and missing data,” Dr. Schandelmaier told Practical Pain Management. “However, because there were very few high-quality trials, none of the previous reviews assessed the relationship between risk of bias and results.”

Low-intensity pulsed ultrasound does not promote bone healing or reduce pain.

LIPUS treatments have long been considered a means to better radiographic bone healing in patients with new fractures. Indeed, a recent review on LIPUS,2 stated that it reduced the time needed for radiographic fracture union, but relied on evidence from a high-risk pool, without accounting for patient outcomes, such as pain relief or reoperation.

However, the recent TRUST clinical trial examined both radiographic and patient outcomes from a large, multicenter population, and did not find evidence that LIPUS accelerated radiographic healing, nor did it appear to aid in functional recovery.3

“Following publication of the TRUST pilot and TRUST trial, there was enough high-quality evidence to explore the possibility that differences in treatment effects could be explained by bias. Only studies deemed at high risk for bias found that LIPUS is effective,” Dr. Schandelmaier explained.

In this new review, Dr. Schandelmaier and his team put together a panel of expert surgeons, methodologists, a physiotherapist, and 4 patients who helped identify specific clinical outcomes that were considered necessary and expected, including:

  • Functional recovery (time to return to work and achieve full weight-bearing)
  • Pain reduction
  • Number of subsequent re-operations

Two reviewers also independently conducted a risk of bias assessment of all 26 studies, including the TRUST trial, using the Cochrane instrument.4 Out of these studies, 6 were considered at low risk of bias, with the remaining 20 classified as having a high risk of bias.

LIPUS Ineffective on Functional Outcomes and Pain

To date, the TRUST trial has been the only study to consider the length of time to return to work using a time-to-event analysis. The findings refuted any significant effect on time to return to work for patients.3 Results were similar for other outcomes, as well, such as time to achieve full weight-bearing, return to leisure activities, and return to initial function prior to injury.

Of the 4 trials that included assessment of pain, LIPUS again provided no significant effect, and when pain intensity was measured, the findings were inconsistent.3 Unfortunately, most studies looking at LIPUS have failed to consider pain and functional outcomes. According to Dr. Schandelmaier, this limitation occurred because these past studies, including the first 2 trials to study LIPUS, focused only on assessing radiographic healing.

“I think it has mainly to do with research traditions,” and the possibility clinicians may have more confidence in objective measures over other patient-centered outcomes,“ said Dr. Schandelmaier. In addition, radiographs are routinely available in clinical practice; they play an important role in confirming a fracture for which subjective measures such as pain are too non-specific,” Dr. Schandelmaier said.

“However, what is true for diagnostic situations does not necessarily apply to evaluation of recovery and therapeutic options, such as LIPUS. Here, pain and function are most relevant and should, therefore, guide the design of clinical trials. This insight is still not as widespread in the research community as it should be,” Dr. Schandelmaier noted.

Unfortunately, much of the research literature on LIPUS has relied on cohorts of various subgroups. Also, some fractures heal much more quickly than others. This might help explain why some past meta-analyses have been noticeably heterogeneous.2,5,6

Granted, if someone were to look at the totality of available literature, regardless of the quality of the studies, the conclusion would be that there is low-quality evidence that LIPUS supports improved radiographic bone healing time. However, even then, Dr. Schandelmaier suggested that doctors may overlook equally significant clinical outcomes, like pain relief, for which high quality evidence suggests no effects.

“This means that, at best, LIPUS might provide patients with visually nicer films, but not reduce their pain, increase their function, or decrease their risk of re-operation. We do not believe that patients or clinicians would find this an acceptable trade-off for the cost and burden of administering LIPUS,” Dr. Schandelmaier concluded.

All relevant conflicts of interest information were submitted to the ICMJE. It should be noted that co-authors Jason W Busse, Diane Heels-Ansdell, and Gordon H Guyatt also were co-authors of the TRUST trial, which received supported in part by an industry grant from Smith & Nephew, which is a manufacturer of LIPUS devices. Click here to access the British Medical Journal's official guideline on the use of LIPUS for bone healing.

Last updated on: March 21, 2017
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