Effectiveness of low-level laser therapy in patients with knee osteoarthritis: a systematic review and meta-analysis.
OBJECTIVE
To investigate the efficacy of low-level laser therapy (LLLT) treatment of knee osteoarthritis (KOA) by a systematic literature search with meta-analyses on selected studies.


METHODS
MEDLINE, EMBASE, ISI Web of Science and Cochrane Library were systematically searched from January 2000 to November 2014. Included studies were randomized controlled trials (RCTs) written in English that compared LLLT (at least eight treatment sessions) with sham laser in KOA patients. The efficacy effective size was estimated by the standardized mean difference (SMD). Standard fixed or random-effects meta-analysis was used, and inconsistency was evaluated by the I-squared index (I(2)).


RESULTS
Of 612 studies, nine RCTs (seven double-blind, two single-blind, totaling 518 patients) met the criteria for inclusion. Based on seven studies, the SMD in visual analog scale (VAS) pain score right after therapy (RAT) (within 2 weeks after the therapy) was not significantly different between LLLT and control (SMD = -0.28 [95% CI = -0.66, 0.10], I(2) = 66%). No significant difference was identified in studies conforming to the World Association of Laser Therapy (WALT) recommendations (four studies) or on the basis of OA severity. There was no significant difference in the delayed response (12 weeks after end of therapy) between LLLT and control in VAS pain (five studies). Similarly, there was no evidence of LLLT effectiveness based on Western Ontario and McMaster Universities Arthritis Index (WOMAC) pain, stiffness or function outcomes (five and three studies had outcome data right after and 12 weeks after therapy respectively).


CONCLUSIONS
Our findings indicate that the best available current evidence does not support the effectiveness of LLLT as a therapy for patients with KOA.
Department of Orthopedic Surgery, West China Hospital, West China Medical School, SiChuan University, ChengDu, SiChuan Province, People's Republic of China.|Duke Molecular Physiology Institute, Duke University School of Medicine, Duke University, Durham, NC, United States.
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Huang
West China School of Stomatology, SiChuan University, ChengDu, SiChuan Province, People's Republic of China.
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Chen
Department of Orthopedic Surgery, West China Hospital, West China Medical School, SiChuan University, ChengDu, SiChuan Province, People's Republic of China.
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Ma
Department of Orthopedic Surgery, West China Hospital, West China Medical School, SiChuan University, ChengDu, SiChuan Province, People's Republic of China.
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Shen
Department of Orthopedic Surgery, West China Hospital, West China Medical School, SiChuan University, ChengDu, SiChuan Province, People's Republic of China.
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Pei
Duke Molecular Physiology Institute, Duke University School of Medicine, Duke University, Durham, NC, United States.|Department of Medicine, Division of Rheumatology, Duke University School of Medicine, Duke University, Durham, NC, United States.
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Kraus
D006801:Humans; D028022:Low-Level Light Therapy; D020370:Osteoarthritis, Knee / Q000503:physiopathology / Q000532:radiotherapy*; D016896:Treatment Outcome
Knee osteoarthritis; Low-level laser therapy; Pain; WOMAC