The largest number of injuries of the knee occurrs in athletes. The portion of girls has reached 30%. More than 50% of all injuries regard the ligaments and the menisci. Especially in these cases and in combined lesions, arthrography gives good results. All possibilities of investigations should be used for acutely injured sportsmen because of the specific risks and the dissimulation of young sportspeople and because of the danger of late established diagnosis and within those of late damages.