[Misunderstanding about the tension band principle in the treatment of patella fractures].

Kirschner's wire tension band was the first choice in the treatment of patella fracture. But the principle of tension band had been misunderstood for long time. In the traditional principle, it was believed that tension band could change the separating force between fracture fragments into compressing stress when exercising. Eccentric fixation and articular surface cracking were disadvantageous. These could make the fracture fragments separate either at resting or exercising, which cause the gaps without pressure. Thus excercising could not change the separating force into compressing stress.