A systematic review of low level laser therapy with location-specific doses for pain from chronic joint disorders

Abstract

We investigated if low level laser therapy (LLLT) of the joint capsule can reduce pain in chronic joint disorders. A literature search identified 88 randomised controlled trials, of which 20 trials included patients with chronic joint disorders. Six trials were excluded for not irradiating the joint capsule. Three trials used doses lower than a dose range nominated a priori for reducing inflammation in the joint capsule. These trials found no significant difference between active and placebo treatments. The remaining 11 trials including 565 patients were of acceptable methodological quality with an average PEDro score of 6.9 (range 5-9). In these trials, LLLT within the suggested dose range was administered to the knee, temporomandibular or zygapophyseal joints. The results showed a mean weighted difference in change of pain on VAS of 29.8 mm (95% CI, 18.9 to 40.7) in favour of the active LLLT groups. Global health status improved for more patients in the active LLLT groups ( relative risk of 0.52; 95% CI 0.36 to 0.76). Low level laser therapy with the suggested dose range significantly reduces pain and improves health status in chronic joint disorders, but the heterogeneity in patient samples, treatment procedures and trial design calls for cautious interpretation of the results.

Eficácia a curto prazo do laser de baixa intensidade em pacientes com osteoartrite do joelho: ensaio clínico aleatório, placebo-controlado e duplo-cego

“…It was decided to study this population because of the high demand for treatment of impaired knee joints. LLLT is a widely used resource in clinics, with well-established therapeutic results (29) , but in relation specifically to knee OA, the results remain controversial (9,14) . Low-level AsGa laser in the infrared spectrum was used because this has deeper penetration than visible red light does (30,31) .…”

Análise da dose do laser de baixa potência em equipamentos nacionais

“…In analyzing these data, it can be seen that the final energy levels obtained in their study were 2.9 J, 3.9 J and 4.8 J, respectively. Bjordal et al 7 stated that doses over 4 J for each point might inhibit fibroblast activity. These studies show that high energy doses do not seem to provide the best effects for tissue repair.…”

“…The ideal dose to be used is based on research in the literature describing successful laboratory practices, and is estimated according to the tissue to be irradiated, and adjusted according to the energy absorbed by each tissue, the duration of irradiation and the size of the affected area 7 .…”

“…Considering that the parameter most described in the literature is the energy density (ΔE), the same value used in different models of equipment may lead to variations in total energy absorbed by the tissue, which may give rise to a variety of effects and may even be harmful to the tissue to which it was applied [7][8][9][10][11][12] .…”

The effects of different doses of 670 nm diode laser on skin flap survival in rats

“…The current challenge for researchers in laser therapy is to find the appropriate parameters (wavelength, output power, emission mode, spot size and shape of the laser beam, length of irradiation, and applied technique) for the therapeutic application to be effective, whether at high or low power, or in photodynamic therapy [10][11][12][13][14] .…”