title: Use of the quadriceps active test to diagnose posterior cruciate-ligament disruption and measure posterior laxity of the knee.
abstract: Orthopaedic surgeons routinely use passive tests, in which the displacing force is applied externally, to evaluate the integrity of the ligaments of the knee. Using a quadriceps active test, in which the muscle contractures of the subject served as the displacing force, tibial displacement was measured with an arthrometer in ninety-two subjects: sixty-seven who had an acute or chronic rupture of the posterior or anterior cruciate ligament and twenty-five who had normal knees. With the knee joint in 90 degrees of flexion, contraction of the quadriceps resulted in anterior translation of the tibia in forty-one of forty-two knees that had a documented disruption of the posterior cruciate ligament. This anterior translation did not occur in the contralateral, normal knee of the same subjects; in the knees of the twenty-five normal subjects; or in twenty-five knees that had a known unilateral anterior cruciate-ligament disruption.
authors.affiliation: Department of Orthopedic Surgery, Kaiser Hospital, San Diego, California.
authors.forename: D M
authors.initials: DM
authors.lastname: Daniel
authors.forename: M L
authors.initials: ML
authors.lastname: Stone
authors.forename: P
authors.initials: P
authors.lastname: Barnett
authors.forename: R
authors.initials: R
authors.lastname: Sachs
mesh_terms: D000293:Adolescent; D000328:Adult; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology; D007718:Knee Injuries / Q000150:complications / Q000175:diagnosis*; D008023:Ligaments, Articular / Q000293:injuries*; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction; D010808:Physical Examination / Q000379:methods*; D012421:Rupture