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Updated: Nov 9, 2025
Knee Arthrocentesis in Adults
Published on: February 25, 2022
Children with Primary Septic Arthritis Have a Markedly Lower Risk of Adverse Outcomes Than Those with Contiguous
Elizabeth C Hamilton1, Mary C Villani1, Mary M Klosterman1
1Children's Health System of Texas, Dallas, Texas.
Insights
Septic arthritis in children with osteomyelitis presents differently than primary septic arthritis, leading to worse outcomes. Differentiating these conditions is crucial for effective treatment and improved long-term results in pediatric joint infections.
Area of Science:
- Pediatric Orthopedics
- Pediatric Infectious Diseases
- Pediatric Rheumatology
Background:
- Septic arthritis in children can lead to severe joint damage and long-term complications if not treated promptly.
- Distinguishing between primary septic arthritis and septic arthritis with contiguous osteomyelitis is critical for risk assessment.
Purpose of the Study:
- To compare outcomes in children with primary septic arthritis versus those with septic arthritis and adjacent osteomyelitis.
- To identify clinical and laboratory differences that influence adverse outcomes in pediatric septic arthritis.
Main Methods:
- Retrospective study of children treated for septic arthritis (with or without osteomyelitis) between 2009-2019.
- Comparison of clinical, laboratory, treatment, and outcome data between two patient cohorts.
Main Results:
- Children with osteomyelitis were older, had higher inflammatory markers (CRP), and more frequent bacteremia.
- Staphylococcus aureus was a more common pathogen in osteomyelitis cases, while Kingella kingae was more prevalent in primary septic arthritis.
- Septic arthritis with osteomyelitis was associated with longer hospitalizations, higher intensive care rates, readmissions, and overall complications.
Conclusions:
- Primary septic arthritis and septic arthritis with contiguous osteomyelitis are distinct conditions in children.
- Contiguous osteomyelitis is a significant driver of adverse outcomes in pediatric septic arthritis.
- Identifying these differences aids in tailoring management, including imaging, antibiotic duration, and follow-up, to mitigate long-term complications.
Background:
It is widely believed that septic arthritis poses a risk of joint destruction and long-term adverse outcomes for children if not treated emergently. In the present study, children who had primary confirmed septic arthritis were compared with those who had septic arthritis and adjacent osteomyelitis to evaluate differences that affect the relative risk of adverse outcomes.
Methods:
Children who underwent multidisciplinary treatment for septic arthritis with or without contiguous osteomyelitis between 2009 and 2019 were retrospectively studied. Clinical, laboratory, treatment, and outcome data were compared between cohorts of children with primary confirmed septic arthritis and children with septic arthritis and contiguous osteomyelitis.
Results:
One hundred and thirty-four children had primary confirmed septic arthritis, and 105 children had septic arthritis with contiguous osteomyelitis. Children with osteomyelitis were older (median, 7.4 versus 2.4 years), had higher initial C-reactive protein (median, 15.7 versus 6.4 mg/dL), and had a higher rate of thrombocytopenia (21.0% versus 1.5%). They also had a higher rate of bacteremia (69.5% versus 20.2%) for a longer duration (median, 2.0 versus 1.0 days). Detected pathogens in children with osteomyelitis as compared with those with primary septic arthritis were more likely to be Staphylococcus aureus (77.1% versus 32.1%) and less likely to be Kingella kingae (2.9% versus 32.1%). Children with contiguous osteomyelitis had longer hospitalizations (median, 8.0 versus 4.0 days), a higher rate of intensive care (21.0% versus 1.5%), a higher readmission rate (17.1% versus 5.2%), and a higher complication rate (38.1% versus 0.7%).
Conclusions:
Primary septic arthritis in children is dissimilar to septic arthritis associated with osteomyelitis. The present study demonstrates that long-term adverse outcomes in children with septic arthritis are likely due to the contiguous osteomyelitis. Children with primary septic arthritis are sufficiently distinguishable from those who have contiguous osteomyelitis to guide decisions for magnetic resonance imaging acquisition, duration of antibiotic therapy, and length of outpatient follow-up in order to recognize and address adverse outcomes.
Level Of Evidence:
Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.
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