Changes in synovial fluid biochemical markers following arthroscopic surgery in patients with knee osteoarthritis

Although arthroscopic surgery (AS) for knee osteoarthritis has been widely employed, scientific evidence is lacking. The purpose of this study was to investigate temporal changes in synovial fluid levels of biochemical markers associated with cartilage metabolism following AS. Twenty-five knees of 24 patients with medial knee osteoarthritis (mean age 70.5 years) were included in this study. Synovial fluids were sampled immediately before surgery and 2, 4, 8, and 12 weeks after AS. Levels of the biochemical markers chondroitin 6-sulfate (C6S), chondroitin 4-sulfate (C4S), and keratan sulfate (KS) were measured and correlations among the biochemical markers were analyzed before and after surgery. C6S, C4S, and total CS levels were the same before and after surgery; however, the KS level decreased significantly at 2 weeks after AS. A strong, positive correlation was detected between C6S and KS levels at 12 weeks, differing from the weaker correlation seen before surgery. Seven of the patients required total or unicompartmental knee arthroplasties in the 2 years following AS. In this study, the significant reduction in KS levels and the strong correlation between C6S and KS levels were shown, which indicates suppressed cartilage turnover after AS. Exploring predictive factors indicating favorable or unfavorable outcomes from AS will be important future studies.