Slipped upper femoral epiphysis--a case of a 'dodgem hip'.

A 15-year-old male patient of slim habitus presented three times over 3 days to the emergency department. Four weeks prior to the first attendance, he apparently injured his left knee in a sudden jolt whilst going on a 'bumper car' (dodgems) at a funfair. Since this incident, he had walked with a limp due to the pain in his left knee.