Experiments were conducted in 20 rabbits to study the effects of a single measured trauma applied to the femoral articular cartilage. The author found that, at the fifteenth day, there was fibrillation localised to the area of the trauma associated with necrosis of superficial chondrocytes and clusters of young chondrocytes. Fissures in the cartilage can be seen to be lined by chondrocytes in clusters. These findings are similar to those described by other authors after different types of injury (contusion, defect, instability, repeated trauma).