Meniscal tears usually result from which of the following circumstances?

Most meniscal tears are produced by flexion and rapid rotation. A classic example ("football knee") involves a player who is hit while running. The knee, supporting all the player's weight, usually is slightly flexed, and the foot is anchored to the ground by cleats. Impact from an opposing player usually causes rotation almost entirely restricted to the knee. The injury involves rapid rotation of the flexed femoral condyles about the tibial plateau, which most frequently tears the medial meniscus. (Less frequently, the lateral meniscus is torn.) A tear in the inner free border of the cartilage is also common whenever excessive rotation without flexion or extension occurs. Early surgical removal of the displaced menisci is usually recommended to prevent further damage to the cartilage or ligaments.