Predictors of Septic Arthritis in the Adult Population

Abstract

Septic arthritis is a devastating condition; well-established criteria for diagnosis exist in the pediatric population, but not for adults. This study evaluated patient factors and laboratory parameters that may be associated with the diagnosis of septic arthritis in adults. A total of 458 knee aspirates for suspected septic arthritis were evaluated with serum and synovial leukocyte counts and differentials as well as Kocher criteria for pediatric septic arthritis. Twenty-two patients (4.8%) had septic arthritis confirmed by a positive synovial fluid culture. Erythrocyte sedimentation rate (ESR) and serum white blood cell (WBC) counts were not statistically different between the 2 groups, with 64% of septic arthritis patients having a normal serum WBC count and 77% being afebrile. Mean synovial fluid WBC count was 26,758 cells/µL and 70,581 cells/µL in the nonseptic and septic groups, respectively. The likelihood ratio for a synovial fluid WBC count greater than 65,000 cells/µL was 2.8 (95% confidence interval, 1.2-6.7). Evaluation receiver operating characteristic curves using synovial WBC counts resulted in a significant area under the curve of 0.66 (P=.02). To achieve 90% specificity, a WBC cutoff of 64,000 cells/µL was required with a corresponding sensitivity of 40%. There was no significant difference in the synovial cell differential of 80% vs 90% in diagnosing infection. Synovial fluid WBC count greater than 64,000 cells/µL yielded the optimal combination of sensitivity and specificity. Polymorphonuclear leukocytes, ESR, serum WBC count, fever, and weight-bearing status were not significant predictors of septic arthritis. This study demonstrates the limited utility of Kocher criteria in the adult population and the importance of synovial leukocyte counts. [Orthopedics. 2016; 39(4):e657-e663.].

The difference between native septic arthritis and prosthetic joint infections: A review of literature

“…Synovial fluid analyses are not included in the definition for SA, as opposed to PJI, but they could be a valuable addition. 18,45,53,54 Radiographs should be analyzed for periosteal reaction, osteolysis, and bony resorption without implant wear or the absence of it can have clinical consequences for the diagnostic pathways and treatment. 3,55 For other ways of radiographic imaging, there might be a small role in both pathologies, however for PJIs, this is highly debated.…”

A Real Pain: Diagnostic Quandaries and Septic Arthritis

“…An SF WBC count of Ն64,000/l was recently shown by Borzio et al to have a sensitivity of 90% for the diagnosis of SA, with a likelihood ratio (LR) of 2.8 (95% confidence interval [CI], 1.2 to 6.7). However, the corresponding specificity was only 40% (25). In an earlier analysis, an SF WBC count of Ն100,000/l had an LR of 28.0 (95% CI, 12.0 to 66.0).…”

Successful treatment with mepolizumab for allergic bronchopulmonary mycosis complicated with bilateral septic arthritis of the knee joints caused by Methicillin-resistant Staphylococcus aureus

“…Septic arthritis is an infection in a joint, often destructive, and usually caused by bacteria. Predisposing factors include advanced age, pre-existing joint disease, skin or soft tissue infection, intravenous drug use, immunosuppression, and recent joint surgery or injection [ [25] , [26] , [27] , [28] ]. Although the knee is the most common joint involved in septic arthritis (>50%) [ 29 ], bilateral involvement is rare.…”