<p>Surgical site infection (SSI) is a prevalent complication in orthopedic surgery, leading to significant morbidity and potentially severe outcomes. This study aimed to identify predictors of SSI in patients undergoing closed patellar fracture surgery. We retrospectively analyzed 2664 patients treated for closed patellar fractures at two hospitals from November 2013 to January 2023. Patients were divided into SSI and non-SSI groups. We employed univariate analysis, logistic regression, and receiver operating characteristic (ROC) curve analyses to evaluate demographic data, comorbidities, and preoperative laboratory results. The SSI rate was 1.4% (38 of 2664 patients). Univariate analysis revealed significant predictors of SSI, including higher preoperative globulin measured at admission (first blood draw) (<i>p</i> = 0.024), high-energy trauma (<i>p</i> &lt; 0.001), higher ASA scores (<i>p </i>= 0.016), and prolonged preoperative stay (<i>p</i> = 0.013). Logistic regression confirmed these factors as independent predictors: elevated GLOB levels (<i>p </i>= 0.001, OR 1.108), high-energy trauma (<i>p</i> = 0.004, OR 2.674), higher ASA scores (<i>p</i> = 0.044, OR 2.228), and prolonged preoperative stay (<i>p </i>= 0.013, OR 1.075). Conversely, high albumin (ALB) levels were protective against SSI (<i>p</i> = 0.002, OR 0.918). ROC analysis determined the cut-off values for predicting SSI as 21.98&#xa0;g/L for GLOB and 8&#xa0;days for preoperative stay. Elevated preoperative GLOB levels, high-energy trauma, higher ASA scores, and extended preoperative stays were found to be independent predictors of SSI in closed patellar fracture surgery. Conversely, high ALB levels were protective. These findings are exploratory and underscore the importance of timely surgery and routine biomarker assessment; confirmation in larger, prospectively collected cohorts with standardized antimicrobial prophylaxis and prevention bundles is warranted.</p>