Synovial fluid and serum levels of a disintegrin and metalloproteinase with thrombospondin motifs 5 are associated with the severity of primary knee osteoarthritis.

BACKGROUND: Knee osteoarthritis (KOA) is a prevalent and disabling joint disease. A Disintegrin and Metalloproteinase with Thrombospondin Motifs 5 (ADAMTS5) regulates cartilage degradation, yet its clinical relevance as a biomarker in KOA severity remains unclear. This study aimed to evaluate the diagnostic value of ADAMTS5 levels in synovial fluid and serum for assessing KOA severity. METHODS: This study enrolled 34 patients with primary KOA and 34 healthy controls. Patients were classified into mild (n = 10), moderate (n = 13), and severe (n = 11) groups according to the Kellgren-Lawrence (K-L) grade. ADAMTS5 levels were measured using enzyme-linked immunosorbent assay. Correlations were assessed using Spearman's correlation coefficient. The diagnostic value was assessed using the Receiver Operating Characteristic (ROC) curve analysis. Predictors of severe KOA was evaluated using multivariate logistic regression analysis. FINDINGS: ADAMTS5 levels in both synovial fluid and serum were significantly higher in the KOA group than that in controls and increased progressively with disease severity. There was a strong positive correlation between ADAMTS5 levels and KOA severity. Furthermore, ADAMTS5 levels in both synovial fluid and serum showed strong diagnostic potential for distinguishing between KOA severity stages. However, ADAMTS5 levels had no independent predictive value for severe KOA. INTERPRETATION: ADAMTS5 levels are significantly elevated in primary KOA and are closely associated with disease severity, suggesting its potential as a candidate biomarker that warrants further validation in future studies.