title: The 6 degrees of freedom kinematics of the knee after anterior cruciate ligament deficiency: an in vivo imaging analysis.
abstract: BACKGROUND
  Previous studies of knee joint function after anterior cruciate ligament deficiency have focused on measuring anterior-posterior translation and internal-external rotation. Few studies have measured the effects of anterior cruciate ligament deficiency on 6 degrees of freedom knee kinematics in vivo.
  
  
  OBJECTIVE
  To measure the 6 degrees of freedom knee kinematics of patients with anterior cruciate ligament deficiency.
  
  
  METHODS
  Controlled laboratory study.
  
  
  METHODS
  The knee joint kinematics of 8 patients with unilateral anterior cruciate ligament rupture was measured during a quasi-static lunge. Kinematics was measured from full extension to 90 degrees of flexion using imaging and 3-dimensional modeling techniques. The healthy, contralateral knee of each patient served as a control.
  
  
  RESULTS
  Anterior cruciate ligament deficiency caused a statistically significant anterior shift (approximately 3 mm) and internal rotation of the tibia (approximately 2 degrees ) at low flexion angles. However, ligament deficiency also caused a medial translation of the tibia (approximately 1 mm) between 15 degrees and 90 degrees of flexion.
  
  
  CONCLUSIONS
  The medial shift of the tibia after anterior cruciate ligament deficiency might alter contact stress distributions in the tibiofemoral cartilage near the medial tibial spine. These findings correlate with the observation that osteoarthritis in patients with anterior cruciate ligament injuries is likely to occur in this region.
  
  
  CONCLUSIONS
  The data from this study suggest that future anterior cruciate ligament reconstruction techniques should reproduce not only anterior stability but also medial-lateral stability.
authors.affiliation: Bioengineering Laboratory, GRJ 1215, Massachusetts General Hospital, 55 Fruit Street, Boston, MA 02114, USA.
authors.forename: Louis E
authors.initials: LE
authors.lastname: Defrate
authors.forename: Ramprasad
authors.initials: R
authors.lastname: Papannagari
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Gill
authors.forename: Jeremy M
authors.initials: JM
authors.lastname: Moses
authors.forename: Neil P
authors.initials: NP
authors.lastname: Pathare
authors.forename: Guoan
authors.initials: G
authors.lastname: Li
mesh_terms: D000328:Adult; D016118:Anterior Cruciate Ligament / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D000070598:Anterior Cruciate Ligament Injuries; D001696:Biomechanical Phenomena; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging / Q000503:physiopathology; D005471:Fluoroscopy; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007718:Knee Injuries / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D008279:Magnetic Resonance Imaging; D008297:Male; D016059:Range of Motion, Articular; D012399:Rotation; D012421:Rupture / Q000473:pathology / Q000503:physiopathology; D013314:Stress, Mechanical; D013977:Tibia / Q000000981:diagnostic imaging / Q000503:physiopathology