The shoe-surface interface and its relationship to football knee injuries.

I he high incidence of severe knee injuries occurring in American football constitutes a national health problem of considerable magnitude. Estimates based on available data 1. project an incidence of 100,000 to 130,000 knee injuries among professional, collegiate, scholastic and sandlot players each season. Of these, between 30,000 to 50,000 sustain injuries requiring surgery. To state the problem in terms of human suffering as well as short and long term disability is not possible. There can be no question but that the knee injury problem demands the attention of all individuals responsible for the health and well being of these athletes. It is recognized that in the vast majority of instances, fixation of the foot on the ground is a necessary element in the mechanism of football knee injuries. With the foot fixed, application of a force stressing the knee in a plane other than that of normal joint motion results in injury if the force exceeds the elastic capabilities of the structure(s) being stressed. Hanley3 was first to recognize this, attributed foot fixation to be due primarily to the heel cleats, and replaced them with a three inch diameter plastic heel disc. Wearing this device resulted in a significant decrease in knee and ankle injuries among Bowdoin College varsity players in 1965 and 1966. Similarly, Nedwidek’ demonstrated that by substituting oblong cleats for the -1/4 inch conical heel cleats in a