Paper 36: Levels of Synovial Fluid Cytokines Predict Midterm Patient Reported Outcomes Following Arthroscopic Partial Meniscectomy

OBJECTIVES: To identify synovial fluid biomarkers associated with midterm postoperative outcomes in patients undergoing arthroscopic partial meniscectomy (APM). METHODS: Subjects were prospectively enrolled in a cohort of patients who had synovial fluid aspirated from their knee on the day of surgery prior to undergoing APM. Biomarker analysis was performed. Preoperative patient-reported outcome (PRO) scores including VAS pain, Lysholm and Tegner activity score were collected preoperatively. At a minimum of 2 years of follow-up postoperative outcomes were collected. Using previously described values, patients who met the minimal clinically important difference (MCID) for Lysholm score were identified and groups were compared using parametric and non-parametric tests. Using preoperative and postoperative outcome scores, generalized linear models were used to explore the relationship between biomarkers and improvement in Lysholm Score, improvement in visual analog scale (VAS) pain score, and postoperative KOOS-PS. RESULTS: Fifty patients were included in the study. 34 (68%) met the MCID for the Lysholm score and 16 (32%) did not. Mean age was 51 ± 9 years for the entire cohort, with no statically significant differences between the groups (p=0.35). Both groups were majority male (p=0.37) and there were no differences in BMI (0.74) or follow-up time (p=0.20). On logistic regression, increased concentration of RANTES (β = -6.30, p = 0.04) and MMP-3 (β = -15.16, p = 0.001) were predictive of less improvement in VAS pain. . For Lysholm score, higher SF levels of IL-1 RA were predictive of greater improvement (β = 12.57, p = 0.04) while higher levels of MMP-3 were predictive of reduced improvement (β = -10.34, p = 0.007). CONCLUSIONS: This study found that at the time of surgery, intraarticular levels of MMP-3 and RANTES are predictive of poorer midterm outcomes and higher pain levels following APM. Additionally, higher levels of IL-1RA at the time of surgery were associated with greater improvement in midterm Lysholm score.