In brief: The authors have seen an increase in anterior cruciate ligament injuries in recent years. In a study of 3,074 Alpine skiers at the Killington Mountain Clinic and the Rutland Regional Medical Center in Vermont, there were more anterior cruciate ligament injuries than tibial fractures. The outcome for the skier with anterior cruciate ligament disruption depends on early, accurate diagnosis of the injury in its acute state. Often this injury is misdiagnosed. The authors have found that the modified Lachman test, in which the patient is sitting rather than lying supine, makes diagnosis of anterior cruciate ligament injuries easier. In addition, the modified version is easier to teach and perform than the standard Lachman test.