The limping child.

Limping is a symptom of varied diagnoses in children and adolescents and can present a difficult diagnostic challenge for primary care clinicians. A careful and systematic evaluation can shorten the long list of potential diagnoses to direct appropriate diagnostic tests to determine the cause of the problem. Trauma and infections are the most common causes of limping. Inflammatory conditions, developmental diagnoses,and overuse injuries are other causes. Although rare, malignancies such as osteosarcoma and blood cell cancers must also be considered as potential causes of limping in children and adolescents.• Limping presents a diagnostic challenge due to the number of possible causes.• On the basis of consensus, diagnostic laboratory tests that include complete blood count, erythrocyte sedimentation rate,C-reactive protein, and blood cultures should be ordered if suspicion is high for infectious etiology.• On the basis of consensus, orthopedic emergencies are vascular compromise, compartment syndrome, and open fractures.• On the basis of moderate evidence and consensus, compartment syndrome in children presents with the three "As" analgesia,anxiety, and agitation. (4)• On the basis of strong evidence and consensus, septic arthritis asa diagnosis increases with the number of Kocher criteria present(temperature >38.5°C, white blood cell count >12,000/mL[12109/L], erythrocyte sedimentation rate >40 mm/h, and inability to bear weight). (8)• On the basis of moderate evidence and consensus, laboratory studies are not always definitive for diagnosis of juvenile idiopathic arthritis. (13)• On the basis of consensus, it is always important to examine the joint above and the joint below the area of the chief compliant,specifically when looking at slipped capital femoral epiphysis and Legg-Calvé-Perthes disease.