Ann K Ketz, Juanita Anders, Judy Orina, Betty Garner, Misty Hull, Nicholas Koreerat, Jeff Sorensen, Candice Turner, James Johnson

Published in: International Journal of Sports Physical Therapy, 2024, 19(1); DOI: 10.26603/001c.90589

The purpose of this study was to assess the clinical impact of photobiomodulation therapy (PBMT) on pain and function in people with plantar fasciitis (PF). Specifically, the authors wanted to compare a standardized dose (10J/cm2) with different output power to see if outcomes were different.

Design
Prospective, randomized controlled clinical trial

Participants
114 patients who were between 18-65 with symptoms of PF for at least 3 months were included and randomized into 3 groups.

  • Usual Care (UC) – 6 week exercise program completed daily
  • UC + PBMT delivered at 10W
  • UC + PBMT delivered at 25W
  • PBMT treatments were delivered 3x/week for 3 weeks using a 25 W high power LightForce® therapy laser

Results

Pain and function were measured over a short term (6 weeks) for all groups and long term (6 months) for the PBMT groups.

  • Pain
    After the 3 weeks of treatment, participants treated with PBMT (10W or 25W) had reductions in pain compared to the usual care group. The pain reduction was greater than 2 points on the visual analogue scale, meaning that the reduction was CLINICALLY meaningful as well as statistically significant. This reduction in pain was maintained out to 6 weeks. There were no differences between the 10W and 25W PBMT groups. It was also found that participants in the PBMT groups used less pain medication (non-steroidal anti-inflammatory drugs) over time than the usual care group. Long-term follow-up showed stable pain scores in both PBMT groups.
  • Function
    Both PBMT groups had clinically significant changes in the sports subscale of the Foot and Ankle Ability Measure compared to the usual care group.
  • Tolerance
    No adverse events were reported for PBMT treatment indicating that treatment is safe. All participants tolerated treatment well, regardless of Fitzpatrick skin scale.

Take Home Message

  • PBMT added to usual care resulted in significant improvement of pain compared to usual care only and the improvement was maintained for up to 6-months follow-up.
  • Dosing is key! 10J/cm2 is a safe and effective dose for treating patients with plantar fasciitis. Increasing output power allows for safe and effective treatment at a faster rate of delivery.

Why were the outcomes similar for 10W and 25W?

  • It makes sense that since plantar fascia is not a deep tissue, higher power/irradiance is not required to provide effective treatment. Additional studies should be done in deeper tissues to reinforce the benefits of higher power.
  • It is important to note the benefit in this study of using the higher power 25W laser which allowed clinicians to treat 2.5x faster than when using 10W.

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