An in-depth study of 74 motor vehicle accidents involving 222 people revealed that 57 of the 153 people injured sustained 69 knee injuries from contact with the instrument panel. There were 51 mild, 10 moderate, and 8 severe knee injuries. Low force contact caused bruising, and more serious injuries occurred when a greater magnitude of force was applied. Injury was most severe when this force was concentrated in a small area and caused lacerations, fractured patella, and open wounds of the joint. Legs trapped under the dashboard with simultaneous rotational, varus, valgus, or frontal forces by the inertial motion of the body produced serious injuries similar to those recieved in sports. Degenerative arthritis was more likely to occur in the seriously injured knees, but generally was not predictable. Long-term disability might be mitigated by early diagnosis and treatment of the specific injury.