The predictive value of preoperative neutrophil-lymphocyte ratio (NLR) on the recurrence of the local pigmented villonodular synovitis of the knee joint.

BACKGROUND: To explore and evaluate the predictive value of preoperative Neutrophil-lymphocyte ratio (NLR) on the recurrence of pigmented villonodular synovitis (PVNS) of the knee joint treated by arthroscopic surgery combining local radiotherapy.

METHODS: Sixty pathological-proven PVNS cases of the knee joint in our department from April 2006 to March 2017 were included. All of them are treated by arthroscopic synovectomy combined with adjuvant radiotherapy. The pre-operative hematological indexes such as c-reactive protein (CRP), erythrocyte sedimentation rate (ESR), NLR, Platelet-lymphocyte ratio (PLR) and Lymphocyte-monocyte ratio (LMR) were collected retrospectively and their relationship with postoperative recurrence was analyzed by using univariate and multivariate analysis, the receiver operating characteristic curves (ROC curve), the Kappa correspondence test and the Mc Nemar Chi-square test.

RESULTS: All 60 patients were followed up for a median of 52.8 months (7-138 months) and the recurrence rate is about 23.3% (14/60). There is a significant difference in NLR between the recurrent and non-recurrent group (P = 0.002). It had a certain correlation with postoperative recurrence (correlation coefficient r = 0.438, P = 0.001). The optimal thresholds in ROC curve were 2.42 (sensitivity 71.4%, specificity 78.3% respectively). which had predictive ability for recurrence after arthroscopic treatment.

CONCLUSION: The preoperative NLR is an easy and cost-effective predictor for relapse in PVNS of the knee joint after the arthroscopic surgery combined with local radiotherapy, which is of profound significance to guide clinical work.