ABSTRACT
Seventy percent of knee instabilities (grade II and III) caused by sport activities are the result of injuries to the anterior cruciate ligament (ACL); football and soccer account for 25 % of the pathologic anterior tibial translation due to acute rupture of the ACL (Hirshman et al., 1990). This is in accordance with the notion that the ACL functions as the primary mechanical restraint of anterior tibial displacements (Hsieh and Walker, 1976; Markolf et al., 1976; Piziali et al., 1980) and that in almost all cases of ACL-insufficiency an instability of the knee joint develops (Muller, 1983). The anterior displacement of the tibia is best measured by means of the Lachman test with the knee positioned at 20°–30° of flexion (Donaldson et al., 1985; Askew et al., 1990; Daniel, 1990).
