Advertisement for orthosearch.org.uk
Orthopaedic Proceedings Logo

Receive monthly Table of Contents alerts from Orthopaedic Proceedings

Comprehensive article alerts can be set up and managed through your account settings

View my account settings

Visit Orthopaedic Proceedings at:

Loading...

Loading...

Full Access

General Orthopaedics

The diagnostic utility of gram stain microscopy in paediatric septic arthritis

British Orthopaedic Association 2012 Annual Congress



Abstract

Background

Gram stain microscopy is a routinely requested investigation in the evaluation of septic arthritis in both paediatric and adult patients. Recent evidence suggests that gram stain microscopy has poor diagnostic accuracy in adults with a sensitivity of only 45%, however the diagnostic accuracy remains unknown in children. We sought to establish the diagnostic utility of gram stain microscopy in the diagnosis of septic arthritis in children.

Methods

We conducted a retrospective review of all patients of 16 years and under that underwent aspiration and washout of suspected septic joints in theatre from March 2005 to February 2011. Theatre data were cross referenced with microbiology results and analysed by simple descriptive methods in Excel.

Results

We identified 23 paediatric patients undergoing washout or aspiration of a suspected septic joint during the time period studied. 17 (74%) of the patients were female and the average age was 2 years (Range 1 month–16 years). The most commonly affected joints were Knees (12/23, 52%) and Hips (7/23, 30%), with the remainder of infections occurring sporadically.

There were 9 cases of culture confirmed septic arthritis (39% of all washouts), and these occurred in 5 knees (56%), 3 Hips (33%) and 1 ankle (11%). Organisms were Staphylococcus Aureus (2/8), Coagulase Negative Staphylococcus (2/9), Streptococcus pneumoniae (2/9), Group B Streptococcus (2/9) and Group A Streptococcus (1/9). Gram stain microscopy identified organisms in 3 aspirates both of which were confirmed on extended culture (Sensitivity 33%, Specificity 100%).

Conclusion

Gram stain microscopy identified only 33% of culture positive cases of septic arthritis within this study. Our results suggest that gram stain microscopy lacks the diagnostic accuracy to be used in the exclusion of septic arthritis in the paediatric population.