Raman spectroscopy investigation of load-assisted microstructural alterations in human knee cartilage: Preliminary study into diagnostic potential for osteoarthritis

A preliminary investigation into the diagnostic potential of Raman spectroscopy for assessing pathological articular cartilage was conducted. Five arthritic human tibial cartilages retrieved after total knee arthroplasty were examined using near-infrared (NIR) Raman spectroscopy excited with 647.1 nm lines of a Kr-ion laser. A “healthy” cartilage obtained from cadaver donor was also examined as a control sample. Degradation severity was first visually classified into five grades (Grade 0–VI) on the surface of both medial and lateral zones in each tibial plateau, according to the Collins scale. Raman spectra were then collected from selected zones with different damage severity. A systematic increase in relative intensity ratio between the Raman bands located at 1241 and 1269 cm−1 (amide III doublet) was observed with increasing degradation grades, which could be related to structural changes under loading in type II collagen. This finding suggests that the present spectroscopic approach might be useful for recognizing and quantitatively assessing the degree of osteoarthritis (OA) in its early manifestation stage.