This study aims to elucidate the effects of radiofrequency chondroplasty (RFC), a surgical technique for the treatment of damaged articular cartilage, at a microscopic scale. Here we report about two aspects of the study – a morphological analysis of the treated surface using nonlinear microscopy and Raman spectroscopy, and an investigation into changes in permeability to large and small molecules. Cartilage samples were obtained from 14 total knee replacement surgeries, which were first treated in vivo with a RFC wand (Arthrocare) using standard arthroscopy technique. Samples for the morphological study were imaged for endogenous fluorescence and collagen, and then imaged using a scanning Raman spectroscope. Samples for the permeability study were incubated in medium containing either Rhodamine or fluorescein labeled albumin, before being sectioned and imaged under a confocal microscope. The morphological study revealed a strong increase in fluorescence in the surface 10 µm, and depletion in collagen signal in the same region, which restores linearly over the adjacent 20–30 µm. Raman spectroscopy showed a spike in β-carrotein in the highly fluorescent surface. Permeability studies show a decrease in permeability to water and an increase in permeability to large molecules, suggesting a remodelling of matrix pores and implications for cell nutrition.Aim
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