AJSM Webinar Series: ACL Injury and PTOA: Bridging Biology, Imaging, and Machine Learning to Improve Outcomes (Recording)-Sundaram V et al. ACL, Meniscal, and Cartilage Injuries Are Associated With Distinct Synovial Fluid Biomarker Profiles. AJSM 2025. PMID: 41055107

Sundaram V et al. ACL, Meniscal, and Cartilage Injuries Are Associated With Distinct Synovial Fluid Biomarker Profiles. AJSM 2025. PMID: 41055107

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This study examined whether different knee injury patterns are linked to distinct synovial fluid biomarker profiles at the time of arthroscopic surgery. In a cohort of 387 patients undergoing knee arthroscopy, researchers collected synovial fluid before incision and measured 10 biomarkers related to inflammation, tissue breakdown, and repair. Patients had common injury combinations involving the ACL, meniscus, and articular cartilage.<br /><br />Using principal component analysis, the biomarker data clustered into three main profiles. The first profile was strongly pro-inflammatory, driven by VEGF, IL-6, MMP-3, MIP-1b, and MCP-1. This profile was positively associated with ACL and meniscal injury and was also linked to worse preoperative knee function on the Lysholm score. The second profile was anti-inflammatory, dominated by TIMP-1 and TIMP-2, and was inversely associated with cartilage damage severity, suggesting that more severe cartilage lesions were linked to less anti-inflammatory activity. The third, mixed profile included RANTES, bFGF, and IL-1Ra and was associated mainly with ACL injury.<br /><br />The findings suggest that ACL and meniscal injuries tend to produce a pro-inflammatory synovial environment, while cartilage damage is associated with a relative reduction in anti-inflammatory markers. Importantly, the pro-inflammatory profile correlated with poorer baseline knee function, indicating clinical relevance. The authors argue that these biomarker patterns may reflect distinct biological pathways involved in knee degeneration and posttraumatic osteoarthritis, and could eventually help guide pathology-specific treatments.

Keywords

knee injury

synovial fluid biomarkers

arthroscopic surgery

ACL injury

meniscal injury

cartilage damage

inflammation

principal component analysis

osteoarthritis

Lysholm score