The effect of low-level laser in knee osteoarthritis: A double-blind, randomized, placebo-controlled trial

Béla Hegedus, László Viharos, Mihály Gervain, Márta Gálfi

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Abstract

Introduction: Low-level laser therapy (LLLT) is thought to have an analgesic effect as well as a biomodulatory effect on microcirculation. This study was designed to examine the pain-relieving effect of LLLT and possible microcirculatory changes measured by thermography in patients with knee osteoarthritis (KOA). Materials and Methods: Patients with mild or moderate KOA were randomized to receive either LLLT or placebo LLLT. Treatments were delivered twice a week over a period of 4 wk with a diode laser (wavelength 830nm, continuous wave, power 50mW) in skin contact at a dose of 6J/point. The placebo control group was treated with an ineffective probe (power 0.5mW) of the same appearance. Before examinations and immediately, 2wk, and 2 mo after completing the therapy, thermography was performed (bilateral comparative thermograph by AGA infrared camera); joint flexion, circumference, and pressure sensitivity were measured; and the visual analogue scale was recorded. Results: In the group treated with active LLLT, a significant improvement was found in pain (before treatment [BT]: 5.75; 2 mo after treatment : 1.18); circumference (BT: 40.45; AT: 39.86); pressure sensitivity (BT: 2.33; AT: 0.77); and flexion (BT: 105.83; AT: 122.94). In the placebo group, changes in joint flexion and pain were not significant. Thermographic measurements showed at least a 0.5°C increase in temperature-and thus an improvement in circulation compared to the initial values. In the placebo group, these changes did not occur. Conclusion: Our results show that LLLT reduces pain in KOA and improves microcirculation in the irradiated area.

Original languageEnglish
Pages (from-to)577-584
Number of pages8
JournalPhotomedicine and Laser Surgery
Volume27
Issue number4
DOIs
Publication statusPublished - Aug 1 2009

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ASJC Scopus subject areas

  • Biomedical Engineering
  • Radiology Nuclear Medicine and imaging

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