# Septic Arthritis of the Elbow: A 10-Year Retrospective Clinical and Microbiological Review From a Single Center

## TL;DR

This study reviews 241 cases of elbow septic arthritis over 10 years, finding that Staphylococcus aureus is the main cause and that patients with certain conditions face more complications.

## Contribution

The study provides updated clinical and microbiological insights into elbow septic arthritis from a single center over a decade.

## Key findings

- Staphylococcus aureus was the most common pathogen, accounting for 58.8% of isolates.
- Co-trimoxazole resistance was observed in 61.8% of isolates, with high rates in Staphylococcus aureus and MRSA.
- Patients with RA, diabetes, or other comorbidities had longer hospital stays and more complications.

## Abstract

Introduction

In industrialized nations, the incidence of septic arthritis (SA) varies depending on geographic region, socioeconomic status, and age group. The condition is more frequently observed in male individuals, the elderly, and children. Additionally, its prevalence may have increased due to a rise in orthopaedic procedures, an aging population, and higher rates of immunosuppression. Hence, understanding the evolving clinical and epidemiological patterns of SA is crucial, along with identifying the common microbiological causes and pathogens involved.

Material (patients) and methods

A retrospective examination of the case series analysis was conducted. Patients underwent treatment at the Poole General Hospital, specializing in acute orthopaedic cases. Data collection lasted six months, from January 2021 to July 2021. During this time, every individual with a suspicion of primary SA of the elbow joint underwent aspiration. Exclusion criteria included any previous elbow joint surgery, a diagnosis of fungal or tuberculous arthritis, and duration of symptoms >6 months. Means and standard deviations were displayed for the continuous variables. Continuous data were summarized using averages and standard deviations, whilst categorical data was provided as absolute numbers with their corresponding percentages.

Results

A total of 241 patients were included in the study, comprising 200 (83%) male patients and 41 (17%) female patients, with a mean age of 67.47 ± 18.23 years. The most common symptom was pain (81.7%), while fever (>37.8°C) was observed in 3.7% of cases. The mean white blood cell (WBC) count was 11.85 ± 7.2, and C-reactive protein (CRP) levels averaged 103.45 ± 102. Leukocytosis was noted in 48.5% of cases. Comorbidities included hypertension (25.3%), diabetes (12.0%), and immunosuppression (34.0%). Gram stain identified bacteria in 10% of cases, while microbial cultures were positive in 27.1%, with Staphylococcus aureus being the most frequently isolated pathogen (58.8%). Resistance to co-trimoxazole was observed in 61.8% of isolates, with 79.4% being Staphylococcus aureus and 11.7% being methicillin-resistant Staphylococcus aureus (MRSA) (p<0.001). Univariate analysis showed significant associations between rheumatoid arthritis (RA), diabetes, and orthopaedic complications (p<0.01). Patients with clinical complications had a significantly longer hospital stay (17.8 ± 12.4 days vs. 6.43 ± 9.5 days, p<0.01). These findings highlight the importance of regional bacterial trends in guiding antibiotic therapy and patient management.

Conclusions

The findings emphasize the predominant role of Staphylococcus aureus as the causative pathogen, with notable antibiotic resistance patterns, particularly to co-trimoxazole and erythromycin. Despite timely surgical intervention and antibiotic therapy, complications including orthopaedic sequelae and prolonged hospital stays were more common among patients with RA, diabetes, and other comorbidities.