Instrumented measurement of anterior knee laxity in patients with acute anterior cruciate ligament disruption

Am J Sports Med. 1985 Nov-Dec;13(6):401-7. doi: 10.1177/036354658501300607.


Instrumented anterior/posterior laxity measurements were performed on 138 patients evaluated within 2 weeks of injury with their first traumatic knee hemarthrosis. All patients were tested with the MEDmetric Arthrometer model KT-1000 in a knee injury clinic. Seventy-five of the patients had knee arthroscopy. Thirty-three had arthrometer laxity tests under anesthesia. Eighty-seven percent of patients arthroscoped had anterior cruciate ligament (ACL) tears and 41% had meniscus tears. One hundred twenty normal subjects were tested to establish normal anterior laxity values. Three tests were used to evaluate anterior laxity: anterior displacement between a 15 and 20 pound force (compliance index), anterior displacement with a 20 pound force, and anterior displacement with a high manually applied force. Displacement measurements in normal subjects revealed a wide range of normal laxity with a small right knee-left knee difference. For example, the 20 pound anterior displacement range was 3 to 13.5 mm with a right knee-left knee difference (mean +/- SD, 0.8 +/- 0.7 mm). Eighty-eight percent of the normals had a right-left difference of less than 2 mm. In the 53 patients arthroscoped who had complete ACL tears, the anterior laxity measurements performed in the clinic were suggestive or diagnostic of pathologic anterior laxity in 50 patients.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acute Disease
  • Adolescent
  • Adult
  • Aged
  • Anesthesia
  • Arthroscopy
  • Athletic Injuries / diagnosis
  • Female
  • Humans
  • Joint Instability / diagnosis*
  • Joint Instability / etiology
  • Knee Injuries / complications
  • Knee Injuries / diagnosis*
  • Ligaments, Articular / injuries*
  • Male
  • Methods
  • Middle Aged