A 3 year old girl of Afro-Caribbean origin presented to the accident and emergency department with a two week history of right sided hip pain and limp. There was no history of trauma and she was otherwise well with no systemic symptoms. On examination, she walked with a Trendelenburg gait and her right leg was noted to be shortened and externally rotated at rest. The range of movements in her right hip was reduced especially abduction and internal rotation. Otherwise, physical examination was …