Introduction: Evaluation of acute hip pain in children can be challenging, because there are several diagnoses to consider. Most patients have a transient synovitis of the hip, which is a benign and self-limited condition. However, its similarities with other more serious disease make the diagnosis one of exclusion. In the Children’s Hospital of Geneva, children presenting with an acute hip pain are treated according to a specific screening protocol including blood sample with rheumatoid panel, hip ultrasound, and conventional X-rays. The objective of our study were to assess the efficacy of the screening protocol on the final diagnosis. We also provided a better characterization of transient synovitis of the hip.

Methods: We retrospectively reviewed the medical records of children who had the investigation’s protocol between 1999 and 2003.

Results: 269 medical records were reviewed comprising 66.2% of boys and 33.8% of girls, with a mean age of 5.5 years. Prior to presentation, 68.4% of children reported pain of < 24 hours in duration. Limp or refusal to bear weight was observed in all cases. According to the Kocher’s predictors of septic arthritis of the hip (fever, non weight-bearing, ESR > 40 mm/h, serum WBC count of > 12000 cells/mm3), 62% had zero predictor, 22% had one, 15% two, 1% three, and none four. A positive rheumatoid factor test was found in 18% of children, whereas 16% of patients had a positive antinuclear antibody test. During hospitalisation one child was diagnosed as having septic arthritis. The remaining patients were diagnosed by exclusion as having a transient synovitis of the hip since clinical follow-up was normal at 6 weeks.

Conclusion: Transient synovitis of the hip is a diagnosis of exclusion, and septic arthritis is the main condition to rule out. Using Kocher’s predictors of septic arthritis is useful for distinction between both conditions early at presentation. In our collective, only 3 patients with transient synovitis had a three of four predictors. Our study also showed that screening for a rheumatologic disease should not be done routinely at the first episode of hip pain. Indeed, positive tests were never confirmed with a clinical situation evocative of rheumatologic disease. More selective criteria should be used before doing a rheumatologic panel. Furthermore our work emphasizes the economical impact of a management of this frequent condition with less blood investigations.