Absorption and scattering of laser radiation in articular cartilage during the treatment of the focus of chondropathy

Justification: Osteoarthritis is one of the most common diseases that lead to disability. Arthroscopic laser treatment of articular cartilage is an effective and promising method of treating osteoarthritis, but its technique can be improved due to the results of this study.Purpose: to experimentally evaluate the absorption and scattering coeffi ts of laser radiation with wavelengths λ=1.55 microns and λ=0.97 microns in articular cartilage tissues and to establish the role of these radiations in the mechanism of laser exposure in the treatment of chondropathy.Materials and methods: Th slices with a thickness of 100 microns and 200 microns were made from samples of pig cartilage tissue. The slices were exposed to laser radiation with wavelengths λ=1.55 microns and λ=0.97 microns. The "method of mobile integrating spheres" was used to measure the optical properties of images.Results: When passing through cartilage tissue, the absorption coeffi t for radiation λ=0.97 microns was 0.14±0.02 mm-1 for radiation λ=1.55 microns- 0.8±0.1 mm-1. The scattering coeffi t for radiations with λ=0.97 and with λ=1.55 was 19±2 mm-1 and 3.7±0.4 mm-1, respectively.Conclusion: 1) When passing through the thickness of articular cartilage, the absorption coeffi t (µa) of laser radiation with λ = 0.97 microns is signifi antly lower than that of laser radiation with λ = 1.55 microns. 2) When passing through the thickness of articular cartilage, the scattering coeffi t (µs) of laser radiation with λ= 0.97 microns is signifi antly higher than that of laser radiation with λ = 1.55 microns. With laser treatment of the focus of chondropathy with combined radiation λ=0.97 microns + λ=1.55 microns, radiation λ=1.55 microns "smoothes" the surface of articular cartilage in the focus of chondromalacia, allowing to achieve restoration of the structure of the articular surface, and the radiation parameters λ=0.97 microns in the thickness of articular cartilage allow to trigger photobiomodulation mechanisms in the articular cartilage and the underlying subchondral bone.