Anterior cruciate ligament injury in indoor ball games

Three videorecorded incidents of knee injuries inflicted during indoor ball games are reported. Injuries and especially anterior cruciate ligament ruptures seemed to be triggered in varus loaded knees by femural external rotation, or in valgus loaded knees by femural internal rotation with the pivot shifted to the lateral femurotibial compartment. The observations suggest that it may be to the players' advantage to be trained in not letting their knees sag medially or laterally during side-stepping or sudden changes in speed.