Assessment of the Correlation between Macroscopic ICRS Grading and Histopathological OARSI Scoring in Osteoarthritic...

AimsPrecise evaluation of cartilage damage is essential for the better management of osteoarthritis and treatment of articular cartilage. For accurate evaluation of cartilage damage, direct visual and/or histological assessment of articular cartilage is preferred over radiological or magnetic resonance imaging (MRI) imaging. This study aimed to determine whether, and to what extent, visual macroscopic grading using International Cartilage Repair Society (ICRS) system correlates with microscopic evaluation using the Osteoarthritis Research Society International (OARSI) histopathological scoring in an ex-vivo setting.MethodsA total of 70 articular cartilage sections obtained from 19 osteoarthritic human knees were macroscopically classified using the ICRS grading system and subsequently evaluated histologically using the OARSI scoring system. Spearman's correlation and bivariate linear regression analyses were performed to assess the association between ICRS and OARSI scores. The reproducibility, reliability, and inter- and intra-observer consistency of the OARSI scoring were further evaluated using Bland-Altman analysis, correlation coefficients, Cohen's kappa, Cronbach's alpha, and intraclass correlation coefficients (ICC).ResultsQualitative assessment revealed a progressive increase in OARSI histological scores corresponding to higher ICRS grades. Spearman's correlation and regression analyses demonstrated a weak positive correlation between visual ICRS grading and histological OARSI scoring in early-stage lesions (ICRS grades 0-I; n = 29, r = 0.592, R² = 0.350, p < 0.001), a moderate correlation with the inclusion of moderate-stage lesions (ICRS grades 0-II; n = 47, r = 0.603, R² = 0.364, p < 0.001), and a strong correlation when severely degenerated cartilage was included (ICRS grades 0-III; n = 67, r = 0.811, R² = 0.657, P < 0.001). The analysis of histological OARSI scores demonstrated narrow limits of agreement and minimal inter-observer variability in the Bland-Altman plot, excellent inter- and intra-observer agreement (ICC > 0.85), and almost perfect reliability (Cronbach's α > 0.95).ConclusionThe results of the study demonstrated a stage-dependent association between macroscopic and histological assessments of osteoarthritic cartilage. The findings indicate that macroscopic ICRS grading may serve as a reliable tool for evaluating moderate to advanced stages of cartilage degeneration. However, its utility in early-stage lesions appears limited due to a weaker correlation with OARSI histological scores. Thus, while macroscopic visual evaluation should be interpreted with caution in early-stage degeneration, histological assessment using the OARSI scoring system remains a valuable tool for accurately identifying early degenerative changes.