There is an Association of Synovial Interleukin-6 Levels With Chondral Damage in Anterior Cruciate Ligament–Deficient Knees

Abstract

Background: Osteoarthritis (OA) in the anterior cruciate ligament (ACL)–deficient knee is seen in approximately 50% of affected patients. Possible causes include biochemical or biomechanical changes. Purpose: We sought to study the correlation between inflammatory cytokines and chondral damage in ACL-deficient knees. Methods: Seventy-six male patients who underwent ACL reconstruction were enrolled in a cross-sectional study. Synovial fluid was aspirated before surgery and analyzed for levels of the inflammatory cytokines tumor necrosis factor-α, interleukin-1 (IL-1), and interleukin-6 (IL-6). At the time of ACL reconstruction, the severity of chondral damage was documented as described by the Outerbridge classification. Results: Patients with grade 2 or higher chondral damage were observed to have elevated IL-6 levels when compared to patients who had no chondral damage. Interleukin-6 levels had no correlation with the duration of injury. Conclusion: Elevated levels of IL-6 in synovial fluid were associated with chondral damage in ACL-deficient knees. Further study is warranted to determine whether inflammatory cytokines contribute to the development of OA of the knee after ACL injury.