MCP-1 in synovial fluid as a predictor of inferior clinical outcomes after meniscectomy

Purpose: To evaluate knee intra-articular cytokine concentrations in patients undergoing isolated meniscectomy and determine if these concentrations are associated with clinical outcomes. Methods: Concentrations of ten biomarkers were quantified in synovial fluid aspirated from the operative knees of patients who underwent isolated meniscectomy from 10/2011-12/2019. Patients completed a survey at final follow-up including VAS, Lysholm, Tegner, and KOOS Physical Function Short Form (KOOS-PS). Failure was defined as subsequent TKA or non-achievement of the Patient Acceptable Symptom State (PASS) for knee pain defined as VAS > 27/100. Regression analysis investigating the relationship between cytokine concentrations and failure was performed. Results: The study consisted of 100 patients, including 50 males (50.0%) with a mean age of 51.1 ± 11.7 years, a median BMI of 28.9 kg/m² [25.5, 32.4], and a mean follow-up of 8.0 ± 2.2 years. There were no demographic or clinical differences between failures (n = 41) and non-failures (n = 59) at baseline. Monocyte Chemotactic Protein 1 (MCP-1) concentration was significantly higher in failures than in non-failures (344.3 pg/ml vs. 268.6 pg/ml, p = 0.016). In a regression analysis controlling for age, sex, BMI, symptom duration, length of follow-up, and ICRS grade, increased MCP-1 was associated with increased odds of failure (p = 0.002). Conclusions: The concentration of MCP-1 on the day of arthroscopic meniscectomy was predictive of failure as defined by an unacceptable pain level at intermediate- to long-term follow-up. This finding may help identify patients at high risk for poor postoperative outcomes following isolated meniscectomy and serve as a target for future postoperative immunomodulation research.