title: Tibiofemoral kinematics of the anterior cruciate ligament (ACL)-deficient weightbearing, living knee employing vertical access open "interventional" multiple resonance imaging.
abstract: BACKGROUND
  Our current understanding of tibiofemoral kinematics in the anterior cruciate ligament (ACL)-deficient knee is very limited. Using vertical open-access MRI, it is possible to accurately analyze tibiofemoral motion in patients with isolated rupture of the ACL.
  
  
  METHODS
  Prospective cohort study.
  
  
  OBJECTIVE
  To assess if ACL rupture alters normal knee weightbearing kinematics.
  
  
  METHODS
  Tibiofemoral motion was assessed through the arc of flexion from 0 degrees to 90 degrees in 10 patients with isolated rupture of the ACL in one knee and a normal contralateral knee. Midmedial and midlateral sagittal images were analyzed in all positions of flexion in both knees to assess the tibiofemoral relationship.
  
  
  RESULTS
  In the lateral compartment of the knee, the tibial plateau is persistently subluxed anteriorly throughout the arc of flexion from 0 degrees to 90 degrees (flexion facet center to posterior tibial cortex distance of 15.8 mm +/- 2.9 in ACL-deficient knees compared to 21.4 mm +/- 1.4 in normal knees at 0 degrees extension, P <.0001) when compared to normal knees. The medial tibiofemoral relationship is unchanged compared to normal knees.
  
  
  CONCLUSIONS
  Rupture of the ACL changes tibiofemoral kinematics producing anterior subluxation of the lateral tibial plateau.
  
  
  CONCLUSIONS
  Altered kinematics may explain, at least in part, the increased incidence of secondary osteoarthritis in patients with ACL rupture.
authors.affiliation: Interventional MR Unit, St Mary's Hospital, London.
authors.forename: Martin
authors.initials: M
authors.lastname: Logan
authors.forename: Edward
authors.initials: E
authors.lastname: Dunstan
authors.forename: James
authors.initials: J
authors.lastname: Robinson
authors.forename: Andrew
authors.initials: A
authors.lastname: Williams
authors.forename: Wady
authors.initials: W
authors.lastname: Gedroyc
authors.forename: Michael
authors.initials: M
authors.lastname: Freeman
mesh_terms: D000328:Adult; D016118:Anterior Cruciate Ligament / Q000503:physiopathology*; D000070598:Anterior Cruciate Ligament Injuries; D001696:Biomechanical Phenomena; D005260:Female; D005269:Femur / Q000503:physiopathology*; D006801:Humans; D007718:Knee Injuries / Q000175:diagnosis* / Q000503:physiopathology; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D011446:Prospective Studies; D012421:Rupture; D013977:Tibia / Q000503:physiopathology*; D016474:Weight-Bearing