Plain X-ray | Bilateral anteroposterior and lateral views of the hips may demonstrate slipped upper femoral epiphysis and should be performed urgently in a child aged 10 or older with atraumatic hip or knee pain or restricted hip movement. Also indicated if ongoing limp in a younger child to investigate for Perthes. |
Ultrasound | Can detect effusion but has low sensitivity and specificity for establishing a diagnosis. |
Full blood count (FBC) | May be indicative of infection, leukaemia or malignant bone marrow infiltration. |
Erythrocyte sedimentation rate (ESR) or C-reactive protein (CRP) | Inflammatory markers; historically ESR was used, but it has been shown that CRP (which has a more rapid response to inflammatory disease, is cheaper and gives a result quicker in most labs) is as good a test. NB: Raised inflammatory markers in the absence of corresponding acute phase response in white cell count or platelets should also raise suspicion for malignancy. |
Investigations for atraumatic limping in children.1 4