Unveiling Regional Variations in Articular Cartilage Mechanics Affected by Osteoarthritis

Abstract Due to its biofunction, the mechanics of articular cartilage (AC) is a vital index concerning the lesion of AC, and there are many studies on the relationship between the mechanics of AC and lesions of AC. It is expected that the variation of mechanics of AC can be used as an early diagnosis index of osteoarthritis (OA) or other lesions of AC. In clinical observation, the degradation of AC is region-specific, therefore, to further achieve this goal, the mechanics of AC under different stages of OA at different regions, i.e., medial distal femoral condyle, lateral distal femoral condyle, medial posterior femoral condyle, and lateral posterior femoral condyle, were systematically measured using the deep indentation technique in this study. The results demonstrated that the mechanics of AC in the four regions follow the same trend with the development of OA. Interestingly, the elastic modulus of AC at the stage of OA3 is the smallest among the last three stages of OA. The discovery of this inflection point at the stage of OA3 holds promise for improving our understanding and therapy for OA in the future. This study also highlights the need for future research to focus on the impact of location on the mechanics of AC.