A new study, published yesterday in the BMJ, is casting doubts on the healing benefit of Bioventus‘s Exogen ultrasound bone stimulator.

The Durham, N.C.-based company’s Exogen is designed to use low-intensity pulsed ultrasound to “help stimulate the body’s natural healing process.” Bioventus touts an 86% healing rate for fractures not healing on their own and 38% faster healing of fresh fractures with use of the device.

Results from the trial indicated no benefit from the use of the device, with no difference in time to radiographic healing between the cohorts, no differences to safety outcomes or in any other functional treatments.

Data from the trial also indicated no SF-36 PCS score difference between the LIPUS and the sham cohort.

“Among patients undergoing intramedullary nailing for a tibial shaft fracture the addition of low intensity pulsed ultrasound does not improve functional recovery or accelerate radiographic healing,” study authors wrote.

The trial had sites in the U.S. and Canada and enrolled 501 patients who required surgical repair of tibia fractures to test the effectiveness of low intensity pulsed ultrasound treatments.

Patients were split between either self administered daily LIPUS use, or the use of a sham device until the tibial fracture showed radiographic healing, or 1 year after intramedullary fixation.

Primary outcomes were specified as time to radiographic healing within 1 year of fixation, with a secondary outcome set as the rate of non-union. Additional outcomes included a short form-36 physical component summary scores, time to return to work, return to household activities, return to leisure activities, full weight bearing and return to greater than or equal to 80% of function before injury.

“The FDA approved LIPUS for fracture healing in 1994 on the basis of small trials at high risk of bias that showed that LIPUS accelerated radiographic healing. Many medical devices, however, are approved for sale without randomized trial evidence of important benefit to patients,” study authors wrote. “A study published in 2016 found that of 99 medical devices recently approved by the FDA, 43 were cleared or approved before a clinical study was published. Further, as is the case with LIPUS, device inventors or industry employees are often investigators on clinical trials that are used to gain regulatory approval. Our experience suggests the high desirability of demanding evidence from randomized trials conducted by investigators other than those who will gain financially from clinical use of the device before approval by regulatory agencies.”

In September, Bioventus said it launched the Exogen ultrasound bone healing system in Saudi Arabia.

In July, Bioventus postponed an initial public offering which was slated to raise up to $150 million. The company had planned to float 8.8 million shares at a price range of between $16 and $18, and would have listed on the NASDAQ exchange under the “BIOV” ticker. The proceeds were earmarked for paying down debt.