Review Question - QID 2971

The patient's clinical image reveals a flexed, abducted, and externally rotated left hip. This hip position maximizes intracapsular volume and indicates a left hip effusion as described in the review by Sucato.

Caird et al performed a Level 1 study that concluded that a temperature above 38.5 was the best predictor of septic arthritis followed in decreasing order by CRP, ESR, refusal to bear weight, and serum WBC count. An elevated rheumatoid factor can be seen in juvenile rheumatoid arthritis but fever is not part of the ACR (American College of Rheumatology) criteria. Presence of bacteria on CSF gram stain indicates a diagnosis of bacterial meningitis, which in isolation does not cause a flexed, abducted, and externally rotated hip. Illustration A shows the predicted probability of septic arthritis based on the number of factors present in the patient and compares Kocher's original 4 factors (ESR, WBC, fever, refusal to bear weight) and Caird's addition of CRP as a 5th factor.