Effects of low level laser 904nm knee osteo

Effect of low-level laser therapy (904 nm) and static stretching in patients with knee osteoarthritis: a protocol of randomised controlled trial

Sarah R F Meneses1,2, Eunice Y Docko1, David J Hunter2, Amelia P Marques1.

1. Department of Physiotherapy, Occupational Therapy and Speech Therapy, School of Medicine, University of Sao Paulo, Sao Paulo, Brazil.
2. Royal North Shore Hospital, Rheumatology Department, and Institute of Bone and Joint Research, Kolling Institute, University of Sydney, Sydney, NSW, Australia.

Background: Osteoarthritis is a highly prevalent and disabling disease. This randomised controlled trial aimed to investigate the effect of low-level laser therapy (LLLT) and static stretching exercises, as monotherapy and in combination, on pain, quality of life, function, mobility, knee range of motion (KROM) and hamstring length in participants with knee osteoarthritis (KOA).

Methods: One hundred and forty five people aged 50-75 years with symptomatic radiographic KOA were recruited from the community and randomly allocated to five study groups (n=29 each): LLLTACTIVE + Stretch, LLLTPLACEBO + Stretch, Stretch, LLLT and Control. LLLT consisted of 9 sessions in the combined treatment groups (LLLT + stretching) and 24 sessions when used as monotherapy. The device used was a Galium-Arsenide laser (904nm, 40mW, 3J/point, 27J/knee). Stretching consisted of 7 different exercises repeated for 24 sessions. Treatment frequency was 3x/week. The control group received a booklet. Participants and assessor were blind to treatment allocation. Measurements were taken at baseline and after each intervention. The primary outcome was pain measured by Visual Analogue Scale. Secondary outcomes included quality of life assessed by Western Ontario and McMaster Universities Arthritis Index (WOMAC), function by Lequesne Algofunctional Index, mobility by Timed Up and Go Test (TUG), KROM by goniometry of knee flexion and hamstring shortening by popliteal angle. The statistical method followed the principles of perprotocol analysis.

Results: All groups demonstrated a significant improvement in pain, total WOMAC, Lequesne and TUG following treatment compared to control (both p<.001). Hamstring shortening improved after the combined treatment (LLLT + stretching) (p<.001). The LLLTPLACEBO + Stretch was the only group better than control in improving KROM (p=0.02). On average, there was a 50% improvement in pain, 39% in total WOMAC, 30% in Lequesne and 20% in TUG for all active treatment groups compared to a control. For the combined treatment groups there was a 43% improvement in hamstring length.

Conclusion: Our results suggest that LLLT and static stretching, combined or as monotherapy, were effective in reducing pain and improving quality of life, mobility and function. Only the combined treatment demonstrated improvements in hamstring shortening.

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