Evaluation of predictive factors of septic wrist to avoid overdiagnosis.

ABSTRACT

BACKGROUND: The existing diagnostic criteria for septic wrist are nonspecific, exposing patients with noninfectious etiologies to surgical morbidity. This study aimed to identify predictors differentiating septic wrist from other etiologies. METHODS: An institutional review board-approved retrospective review was conducted on patients with a presumed diagnosis of septic wrist (2003-2022). Bivariate and multiple regression analyses were performed to identify correlation between confirmed septic wrist and comorbidities (autoimmune diseases, immunosuppression, crystalline arthropathy, intravenous [IV] drug use, smoking), penetrating trauma, fever, multi-joint involvement, inflammatory markers (erythrocyte sedimentation rate [ESR]/C-reactive protein [CRP]/white blood cells [WBC]), serum uric acid level, blood cultures, imaging findings, and synovial fluid analysis. Categorical data were reported as median [interquartile range]. RESULTS: Hundred and sixty-eight (58 females and 110 males) patients were included. The median length of hospitalization and follow-up were 6[7] days and 1[3] months. Eighty-nine (53%) patients had septic wrist confirmed with Gram stain/culture, 48 (29%) patients received alternative diagnoses, and 31 (18%) patients had undetermined diagnoses. Concomitant septic wrist and crystalline arthropathy were identified in 9 patients (6.6% of total patients). Out of the 48 patients who received alternative diagnoses, 12 (25%) underwent open drainage. Elevated synovial WBC count (95,409.4 ± 85,926.2) showed a trend of association with septic wrist (p = 0.08). Negative synovial crystals (p = 0.01), positive blood culture (p = 0.04), negative history of crystalline arthropathy (p = 0.08), and multi-joint involvement (p = 0.05) were identified as predictors of septic wrist with a combined sensitivity of 87.5%, specificity of 86.2%, and area under the curve 0.93. CONCLUSIONS: Current diagnostic criteria for septic wrist have low specificity. Negative history of crystalline arthropathy, multi-joint involvement, absence of synovial crystals, and positive blood culture are helpful indicators for predicting septic wrist in patients presenting with a painful, erythematous, and swollen wrist.