This study evaluates the incidence of knee injuries in two series of ski accidents over the last two decades—2004 cases from 1965 through 1971 and 3270 cases from 1975 through 1981. In the latter (1970s) series, an increase in knee injuries (from 21.7% to 26.2%) and a high percentage of severe injuries were observed; 43% of injured skiers had not checked the adjustment of their safety bindings. Results of 24 arthroscopies showed that there were more associated injuries when the initial clinical diagnosis was that of medial collateral ligament rupture. Injuries that have occurred without the skier's actual falling might be related to overstressing of the knee structures in turns. On the basis of a theoretical model of the biomechanical stresses involved in knee injury, the assumption can be made that today's skiing equipment allows the stress to be transmitted to the knee joint.