title: Dynamic Effect of Quadriceps Muscle Activation on Anterior Tibial Translation After Single-Bundle and Double-Bundle Anterior Cruciate Ligament Reconstruction.
abstract: OBJECTIVE
  To examine differences in anterior tibial translation in 3 groups: single-bundle anterior cruciate ligament (ACL)-reconstructed, double-bundle ACL-reconstructed, and ACL-intact knees under gradual dynamic quadriceps muscle activation.
  
  
  METHODS
  Thirty male patients underwent successful single-bundle (n = 15) and double-bundle (n = 15) ACL reconstructions; 15 healthy controls were included in the study. Anterior tibial translation was assessed at 30° of knee flexion in the resting position (0% quadriceps activation) and under 50% and 100% of maximum quadriceps concentric contraction using an isokinetic dynamometer with the KT-2000 arthrometer securely attached to the participants' knees.
  
  
  RESULTS
  The 2 ACL-reconstructed groups were similar regarding International Knee Documentation Committee (IKDC), Knee Injury and Osteoarthritis Score (KOOS), Tegner, and Lysholm scores and preliminary isokinetic evaluation (P = .38). Quadriceps activation significantly affected anterior tibial translation (P = .001, α = 0.98). In all 3 study groups, anterior tibial translation was significantly higher under 100% quadriceps activation compared with 0% contraction (P = .01) and 50% quadriceps activation (P = .047). There were no between-group differences in anterior tibial translation with 0%, 50%, or 100% quadriceps activation (P = .46).
  
  
  CONCLUSIONS
  Under quadriceps muscle activation, anteroposterior knee laxity in ACL-intact and ACL-reconstructed knees is gradually increased. Single-bundle and double-bundle ACL-reconstructed knees show a similar increase in anterior tibial translation under gradual quadriceps contraction. When comparing different ACL reconstruction techniques in the experimental setting, dynamic, in addition to static, testing is advised to reach a comprehensive assessment of anteroposterior knee stability.
  
  
  METHODS
  Level III, retrospective comparative study.
authors.affiliation: Department of Orthopaedic Surgery, Faculty of Medicine, School of Health Sciences, University of Thessaly, Larissa, Greece. Electronic address: tsarouhas_a@yahoo.gr.
authors.forename: Alexander
authors.initials: A
authors.lastname: Tsarouhas
authors.affiliation: Department of Physical Education and Sport Science, Center for Research and Technology of Thessaly, Trikala, Greece.
authors.forename: Giannis
authors.initials: G
authors.lastname: Giakas
authors.affiliation: Department of Orthopaedic Surgery, Faculty of Medicine, School of Health Sciences, University of Thessaly, Larissa, Greece.
authors.forename: Konstantinos N
authors.initials: KN
authors.lastname: Malizos
authors.affiliation: Department of Physical Education and Sport Science, Center for Research and Technology of Thessaly, Trikala, Greece.
authors.forename: Giannis
authors.initials: G
authors.lastname: Spiropoulos
authors.affiliation: Department of Physical Education and Sport Science, Center for Research and Technology of Thessaly, Trikala, Greece.
authors.forename: Vasilios
authors.initials: V
authors.lastname: Sideris
authors.affiliation: Department of Physical Education and Sport Science, Center for Research and Technology of Thessaly, Trikala, Greece.
authors.forename: Yiannis
authors.initials: Y
authors.lastname: Koutedakis
authors.affiliation: Department of Orthopaedic Surgery, Faculty of Medicine, School of Health Sciences, University of Thessaly, Larissa, Greece.
authors.forename: Michael E
authors.initials: ME
authors.lastname: Hantes
mesh_terms: D000328:Adult; D016118:Anterior Cruciate Ligament / Q000601:surgery*; D000070598:Anterior Cruciate Ligament Injuries; D059549:Anterior Cruciate Ligament Reconstruction / Q000379:methods*; D006801:Humans; D007718:Knee Injuries / Q000503:physiopathology* / Q000601:surgery*; D007719:Knee Joint / Q000502:physiology* / Q000601:surgery; D008297:Male; D052097:Quadriceps Muscle / Q000502:physiology*; D012189:Retrospective Studies; D013977:Tibia / Q000502:physiology*; D055815:Young Adult