Septic arthritis of the native knee is a serious condition that requires prompt evaluation and treatment to prevent chondrolysis, joint destruction, and systemic septic complications.1–3 While direct bacterial inoculation may occur in instances of surgery, injections, or trauma, hematogenous inoculation may occur in the setting of sepsis.2–4
In their article in Baylor University Medical Center Proceedings, Modi et al present an analysis of 92,290 patients from the National Inpatient Sample who were diagnosed with nongonococcal septic arthritis of the native knee.5 While this population represented a low proportion of the total admissions (0.045%), there was significant morbidity, mortality, and cost associated with these patients. In-hospital death occurred in 2.5% of patients, and when this group was analyzed, there were more comorbidities and complications, as well as increased length of stay and cost associated with the in-hospital mortality group. Eighty percent of these patients were either admitted with sepsis or diagnosed with sepsis during their hospital stay.
The rate of mortality in this series is lower than in previously reported series.6–9 While this may represent improvement in medical treatment of these critically ill patients, data on treatment of sepsis would not support dramatically improving outcomes.10,11 This finding more likely indicates that in-hospital death does not capture the full extent of morbidity and mortality associated with this patient population.
The nature of this study can show correlation but not necessarily causation, and it is not possible to assess the temporal relationship of the development of comorbidities in the cases of in-hospital mortality. It cannot be determined whether septic knee arthritis led to sepsis and other comorbidities or whether septic arthritis appeared as a consequence of systemic sepsis later in the cascade of multisystem organ failure. The septic knee arthritis may be a primary driver of mortality, a complication of bacteremia and sepsis, or a comorbid condition.
This study provides valuable information on a population level on the morbidity, mortality, and cost of nongonococcal septic arthritis of the native knee. The determination of prognosis or treatment in the individual patient requires the granularity that a database study cannot provide.
—Bryce C. Allen, MD
Vice Chair, Department of Orthopedics
Director of Orthopedic Research
Baylor Scott and White Medical Center, Temple
Associate Professor of Orthopedic Surgery
Baylor College of Medicine – Temple
Temple, Texas, USA
Bryce.Allen@bswhealth.org
http://orcid.org/0000-0001-6379-1485
References
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