title: A 10-year prospective trial of a patient management algorithm and screening examination for highly active individuals with anterior cruciate ligament injury: Part 2, determinants of dynamic knee stability.
abstract: OBJECTIVE
  To clarify the determinants of dynamic knee stability early after anterior cruciate ligament injury.
  
  
  METHODS
  Cohort study (diagnosis); Level of evidence, 1.
  
  
  METHODS
  Three hundred forty-five consecutive patients who were regular participants in International Knee Documentation Committee level I/II sports before injury and had an acute isolated anterior cruciate ligament injury from the practice of a single orthopaedic surgeon underwent a screening examination including clinical measures, knee laxity, quadriceps strength, hop testing, and patient self-reported knee function a mean of 6 weeks after injury when impairments were resolved. Independent t tests were performed to evaluate differences in quadriceps strength and anterior knee laxity between potential copers and noncopers. Hierarchical regression was performed to determine the influence of quadriceps strength, preinjury activity level, and anterior knee laxity on hop test performance, as well as the influence of timed hop, crossover hop, quadriceps strength, preinjury activity level, and anterior knee laxity on self-assessed global function.
  
  
  RESULTS
  Neither anterior knee laxity nor quadriceps strength differed between potential copers and noncopers. Quadriceps strength influenced hop test performance more significantly than did preinjury activity level or anterior knee laxity, but the variance accounted for by quadriceps strength was low (range, 4%-8%). Timed hop performance was the only variable that affected self-assessed global function.
  
  
  CONCLUSIONS
  Traditional surgical decision making based on passive anterior knee laxity and preinjury activity level is not supported by the results, as neither is a good predictor of dynamic knee stability. A battery of clinical tests that capture neuromuscular adaptations, including the timed hop test, may be useful in predicting function and guiding individualized patient management after anterior cruciate ligament injury.
authors.affiliation: Department of Physical Therapy, University of Delaware, Newark, DE 19716, USA.
authors.forename: Wendy J
authors.initials: WJ
authors.lastname: Hurd
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Axe
authors.forename: Lynn
authors.initials: L
authors.lastname: Snyder-Mackler
mesh_terms: D000293:Adolescent; D000328:Adult; D000465:Algorithms; D016118:Anterior Cruciate Ligament / Q000502:physiology; D000070598:Anterior Cruciate Ligament Injuries; D003657:Decision Making; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000503:physiopathology*; D007718:Knee Injuries / Q000145:classification / Q000534:rehabilitation / Q000628:therapy*; D007719:Knee Joint / Q000502:physiology*; D008297:Male; D010808:Physical Examination; D011446:Prospective Studies