Low-level laser therapy in knee osteoarthritis: a narrative review

Knee osteoarthritis (KOA) is a degenerative joint disease that affects the entire knee joint, commonly seen in the elderly, and has shown an increasing trend toward younger populations in recent years. Its main symptoms include pain, swelling, stiffness, and limited mobility; besides, severe cases can lead to disability and complete loss of function.KOA can also lead to psychological issues such as depression and anxiety, posing substantial burdens on patients, families, and society. The current treatment options include physical therapy, medications, and other conservative methods, or surgical treatment. Notably, low-level laser therapy (LLLT) is a non-invasive and safe physical treatment that has been proven to be effective for various conditions affecting the musculoskeletal, nervous, and dermatological systems. Its non-invasive nature avoids the trauma and pain associated with surgery, and it avoids potential side effects of medication. Due to its convenience, safety, and effectiveness, LLLT has been widely recognised as a strategy for treating KOA. This review comprehensively examines the mechanisms of LLLT, including its capacity to modulate synovial macrophage polarisation and regulate the expression of inflammatory factors. It also provides an in-depth analysis of the clinical efficacy of LLLT as a standalone treatment or in conjunction with other therapeutic modalities for KOA patients, drawing on evidence from cellular, animal, and patient studies over recent decades. The aim is to offer robust theoretical support for the treatment of KOA.