In the years 1979-1988 65 patients (62 men and 3 women) with rotary anterior-medial instability of the knee were treated surgically. The average age was 34 years. The cause of injuries (65%) were accidents during work in mines of pit-coal. 52 patients were treated surgically in the period of 7 days after the accident. The remaining 13 ones were operated on after the period of 6 weeks. In the group of patients operated on immediately the most frequently applied procedure was the suture according to O'Donoughe of the injured ligaments and shift of the goose foot according to Slocum and Larson. But when the anterior crucial ligament was broken in the shape of a "brush", its reconstruction was formally made according to Jones. For patients with chronic instability extra-articular plastic operations were performed i.e. shift of the semi-tendinous muscle and shift of the goose foot, as well as intra-articular--in case of injury of the anterior crucial ligament. The period of observation was from 4 to 12 years. Better results were obtained in patients operated on immediately: good result--62%, satisfactory--32% and bad--6%. For all patients with chronic instability the obtained results were only satisfactory.