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Flexiseq trials for osteoarthritis

Only a small number of trials have been published on FLEXISEQ. They have all involved a small group of investigators, several of whom have financial relationships with the companies involved in developing the device.

This doesn’t make the results invalid but it’s important to take into account when thinking about the evidence.

There have been four randomised controlled trials conducted among participants with osteoarthritis of the knee. None of these have been reported by investigators independent of the companies developing the device.

Trial 1 (2007)

In the first trial of 397 particpants treated for six weeks, FLEXISEQ was less effective than a gel containing ketoprofen, a non-steroidal anti-inflammatory drug (NSAID) and celecoxib tablets (a NSAID used to treat mild to moderate osteoarthritis symptoms).

The following percentages of participants rated their response as ‘good’ or ‘excellent’:

  • ketoprofen gel = 46%.
  • celecoxib tablets = 39%
  • FLEXISEQ = 28%

Trial 2 (2013)

In the second trial, 1,395 participants were treated for 12 weeks.

  • FLEXISEQ had similar effectiveness on pain, function and stiffness as a gel containing ketoprofen and celecoxib tablets, and it was more effective than a placebo tablet.
  • Pain reduction was between 38–41% for all the treatments, compared to 29% reduction in those taking inactive tablets.

If this study had included a truly inactive gel as comparison it would have allowed us to be more certain whether the difference was real or not.

Trial 3 (2013)

866 participants were treated for 12 weeks:

  • Participants using gels containing different doses of ketoprofen were all more likely to improve than persons using FLEXISEQ (using an internationally accepted definition of “improvement”).
  • Most participants using FLEXISEQ did improve.

Trial 4 (2013)

FLEXISEQ was compared to a gel with ketoprofen in 555 participants treated for 12 weeks.

  • Participants using keoprofen gel were less likely to improve compared to those using FLEXISEQ.
  • Those using FLEXISEQ reported a 40–45% decrease in pain, function and stiffness.


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