title: Anterior knee laxity and loss of extension after anterior cruciate ligament injury.
abstract: This study was performed to examine the relationship between knee extension loss and the length of time after injury. We also wanted to compare anterior laxity in anterior cruciate ligament-injured knees in the early and late stages of injury. Loss of knee extension was measured in 81 patients with anterior cruciate ligament injury using lateral radiography with the injured leg relaxed and elevated. Extension loss was defined as the difference in maximal extension angle between the injured and uninjured knees. Average loss of extension was 3.6 degrees in the 17 knees in which the anterior cruciate ligament had been torn 3 weeks or less before examination (the acute injury group) and 0.6 degree in the 64 knees in which the anterior cruciate ligament had been torn more than 3 weeks before examination (the chronic injury group). The extension loss in the acutely injured knees was significantly greater compared with that in the uninjured knees and in the chronically injured knees. Arthrometric measurements using the KT-1000 arthrometer were reliable to diagnose an acute tear. There was no correlation between the degree of extension loss and arthrometric anterior knee laxity measurements. In 12 patients, the initial extension deficit in the early stage of injury significantly resolved with time, and manual maximum arthrometric measurements of anterior knee laxity improved spontaneously with time.
authors.affiliation: Department of Orthopaedic Surgery, Tokyo Medical and Dental University, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Muneta
authors.forename: Y
authors.initials: Y
authors.lastname: Ezura
authors.forename: I
authors.initials: I
authors.lastname: Sekiya
authors.forename: H
authors.initials: H
authors.lastname: Yamamoto
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D016118:Anterior Cruciate Ligament / Q000000981:diagnostic imaging; D000070598:Anterior Cruciate Ligament Injuries; D002908:Chronic Disease; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000000981:diagnostic imaging / Q000209:etiology*; D007718:Knee Injuries / Q000150:complications* / Q000000981:diagnostic imaging; D007719:Knee Joint / Q000000981:diagnostic imaging / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009126:Muscle Relaxation; D011446:Prospective Studies; D011859:Radiography; D016059:Range of Motion, Articular / Q000502:physiology*; D012044:Regression Analysis; D015203:Reproducibility of Results; D012421:Rupture; D016683:Supine Position; D013997:Time Factors