Dear Colleagues,

In the recent osteoarthritis treatment guidelines established by the National Institute of Health Care Excellence (NICE) in the U.K., therapeutic exercise and weight management are recommended alongside drug medication to alleviate pain, including topical or oral non-steroidal anti-inflammatory drugs (NSAIDs) (or paracetamol if NSAIDs are contraindicated). NSAIDs and paracetamol are known to have harmful side effects. Those devising these guidelines were unable to recommend electrophysical agents, including acupuncture, transcutaneous electrical nerve stimulation, or photobiomodulation therapy (PBMT), due to insufficient high-quality clinical trials to evaluate their benefit or harm.

PBMT applies red and near-infrared light over sites of pathology to facilitate tissue healing, reduce inflammation, and relieve pain. PBMT includes low-level laser therapy (LLLT), high-intensity laser therapy (HILT), and light-emitting diode therapy (LEDT). It is unclear what the optimal PBMT parameters are. Both LLLT and LEDT have been studied for decades, whereas HILT has only recently become available due to advancements in equipment, and is therefore less studied. The results of a systematic review of randomized placebo-controlled trials indicates that LLLT, at ≥4 J with 785–860 nm wavelength and at ≥1 J with 904 nm wavelength per treatment spot, can reduce pain and disability associated with knee osteoarthritis in humans. Likewise, there is some evidence to support the use of LEDT and HILT.

The purpose of this Special Issue of Life is to disseminate research and catalyze debate on all matters related to the use of PBMT in knee osteoarthritis. We invite you to contribute articles on the mechanisms of action, efficacy, effectiveness, factors influencing response, technological advances, utility, and service delivery. We welcome cell and animal studies, clinical trials, narrative and systematic reviews, and viewpoint articles.

Dr. Martin Bjørn Stausholm
Prof. Dr. Jan Magnus Bjordal
Dr. Roberta Chow
Prof. Mark I. Johnson
Guest Editors

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• knee osteoarthritis
• light-emitting diode therapy
• low-level laser therapy
• high-intensity laser therapy
• photobiomodulation therapy