Synovial Fluid mtDNA Predicts Cartilage Damage After Joint Injury

Osteoarthritis (OA) and other forms of articular injury lead to progressive cartilage degradation, causing pain and functional impairment. Current diagnostic methods often rely on imaging or invasive procedures, which may not fully capture the early stages or severity of cellular damage. This study investigated if synovial fluid mitochondrial DNA (mtDNA) concentration could serve as a reliable biomarker for the extent of cartilage damage following natural joint injuries.

The study revealed a significant positive correlation between synovial fluid mtDNA concentration and the severity of cartilage damage. Patients with severe cartilage damage exhibited mtDNA levels that were, on average, 3.5-fold higher (p<0.001) compared to those with mild damage. The most striking finding was that synovial fluid mtDNA concentration showed a strong positive correlation (r = 0.78, p<0.0001) with the arthroscopic cartilage damage score, indicating its potential as a robust biomarker. Furthermore, individuals classified with moderate cartilage damage had mtDNA concentrations 1.8-fold greater (p<0.01) than those with minimal damage. This suggests a dose-dependent relationship where increasing mtDNA levels directly correspond to more extensive cartilage degradation, with a 43% increase in mtDNA observed for every unit increase in cartilage damage score.