The painful hip: evaluation of criteria for clinical decision-making

Children with a painful hip present a diagnostic challenge since clinical d ifferentiation between septic arthritis, transient synovitis and Perthes di sease may be difficult. Septic arthritis, a potentially life-threatening an d debilitating medical emergency, requires early recognition for successful treatment, while transient synovitis and Perthes disease may be managed co nservatively. An "ideal" single test for discrimination between these condi tions is currently not available. We assessed the value of clinical examina tion and simple laboratory tests together with radiography and hip ultrasou nd in differentiating septic arthritis from transient synovitis and Perthes disease by analyzing the records of 89 children treated at our institution for hip pain. Ultrasound, radiographs, laboratory, clinical, and follow-up data were available for all the children. Diagnoses were made according to established criteria. Transient synovitis was present in 64 patients, sept ic arthritis in 8 (of whom 2 had additional osteomyelitis), and Perthes dis ease in 4. All children with septic arthritis had hip effusion shown by ult rasound and at least two of the following criteria: fever, elevation of ery throcyte sedimentation rate (ESR) and of C-reactive protein (CRP). None of the children without effusion on ultrasound or who lacked two or all criter ia had septic arthritis. Radiographs had no significant impact on the decis ion-making in primary evaluation of acute hip pain. Conclusion We conclude that investigation of painful hips in children, base d on hip ultrasound, body temperature, ESR and CRP. may allow cases for hip joint aspiration to be selected efficiently and may reduce the number of r adiographs and hospital admissions.