Septic arthritis of the knee

Case contributed by Dr Henry Knipe


Painful right leg post fall three days ago. Unable to weight bear.

Patient Data

Age: 50 years
Gender: Male

Right tricompartmental knee replacement. No fracture identified. Alignment within normal limits. Large knee joint effusion containing locules of gas. Prepatellar soft tissue swelling.

Case Discussion

The locules of gas seen on the lateral projection are the features most concerning for a septic arthritis in what would otherwise be a standard knee joint effusion. The patient proceeded to washout, with synovial biopsy culturing Streptococcus dysgalactiae (Group C/G). The patient will be on long-term antibiotics. 

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Case information

rID: 48799
Published: 25th Oct 2016
Last edited: 14th Aug 2019
Inclusion in quiz mode: Included

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