Legg–Calvé–Perthes disease: pertinent information for orthopaedic exam candidates

Legg–Calvé–Perthes (LCP) disease is a common topic for final professional examinations. It is an important differential diagnosis to recognize in children presenting with a limp. Its diagnosis requires the exclusion of diagnoses requiring more immediate action, such as infection or malignancy. It may also present with subtle, or no, signs on routine investigations. LCP disease may resolve spontaneously without long term sequelae or result in debilitating hip pathology requiring operative management. Its aetiology and most appropriate management are topics for debate, and knowledge of the classical papers and commonly used classification systems allow candidates to discuss these in more depth.