title: Is an Anterolateral Ligament Reconstruction Required in ACL-Reconstructed Knees With Associated Injury to the Anterolateral Structures? A Robotic Analysis of Rotational Knee Stability.
abstract: BACKGROUND
  The effect of an anterolateral ligament (ALL) reconstruction on rotational knee stability and corresponding anterior cruciate ligament (ACL) graft forces using multiple knee loading conditions including the pivot-shift phenomenon has not been determined.
  
  
  OBJECTIVE
  First, to determine the rotational stability and ACL graft forces provided by an anatomic bone-patellar tendon-bone ACL reconstruction in the ACL-deficient knee alone and with an associated ALL/iliotibial band (ITB) injury. Second, to determine the added rotational stabilizing effect and reduction in ACL graft forces provided by an ALL reconstruction.
  
  
  METHODS
  Controlled laboratory study.
  
  
  METHODS
  A 6 degrees of freedom robotic simulator was used to test 7 fresh-frozen cadaveric specimens during 5 testing conditions: intact, ACL-sectioned, ACL-reconstructed, ALL/ITB-sectioned, and ALL-reconstructed. Lateral and medial tibiofemoral compartment translations and internal tibial rotations were measured under Lachman test conditions, 5-N·m internal rotation, and 2 pivot-shift simulations. Statistical equivalence within 2 mm and 2° was defined as P < .05.
  
  
  RESULTS
  Single-graft ACL reconstruction restored central tibial translation under Lachman testing and internal rotation under 5-N·m internal rotation torque ( P < .05). A modest increase in internal rotation under 5-N·m internal rotation torque occurred after ALL/ITB sectioning of 5.1° (95% CI, 3.6° to 6.7°) and 6.7° (95% CI, 4.3° to 9.1°) at 60° and 90° of flexion, respectively ( P = .99). Lateral compartment translation increases in the pivot-shift tests were <2 mm. ALL reconstruction restored internal rotation within 0.5° (95% CI, -1.9° to 2.9°) and 0.7° (95% CI, -2.0° to 3.4°) of the ACL-reconstructed state at 60° and 90° of flexion, respectively ( P < .05). The ALL procedure reduced ACL graft forces, at most, 75 N in the pivot-shift tests and 81 N in the internal rotation tests.
  
  
  CONCLUSIONS
  Although the ALL reconstruction corrected the small abnormal changes in the internal rotation limit at high flexion angles, the procedure had no effect in limiting tibiofemoral compartment translations in the pivot-shift test and produced only modest decreases in ACL graft forces. Accordingly, the recommendation to perform an ALL reconstruction to correct pivot-shift abnormalities is questioned.
  
  
  CONCLUSIONS
  The small changes in rotational stability after ALL/ITB sectioning would not seem to warrant the routine addition of an ALL reconstruction in primary ACL injuries. Clinical exceptions may exist, as in grossly unstable grade 3 pivot-shift knees and revision knees. However, the concern exists of overconstraining normal tibial rotations.
authors.affiliation: Cincinnati Sports Medicine and Orthopaedic Center-Mercy Health, Cincinnati, Ohio, USA.|The Noyes Knee Institute, Cincinnati, Ohio, USA.
authors.forename: Frank R
authors.initials: FR
authors.lastname: Noyes
authors.affiliation: Cincinnati Sports Medicine and Orthopaedic Center-Mercy Health, Cincinnati, Ohio, USA.|The Noyes Knee Institute, Cincinnati, Ohio, USA.
authors.forename: Lauren E
authors.initials: LE
authors.lastname: Huser
authors.affiliation: Cincinnati Sports Medicine and Orthopaedic Center-Mercy Health, Cincinnati, Ohio, USA.|The Noyes Knee Institute, Cincinnati, Ohio, USA.
authors.forename: Darin
authors.initials: D
authors.lastname: Jurgensmeier
authors.affiliation: Cincinnati Sports Medicine and Orthopaedic Center-Mercy Health, Cincinnati, Ohio, USA.|The Noyes Knee Institute, Cincinnati, Ohio, USA.
authors.forename: James
authors.initials: J
authors.lastname: Walsh
authors.affiliation: Department of Operations and Business Analytics, College of Business, University of Cincinnati, Cincinnati, Ohio, USA.
authors.forename: Martin S
authors.initials: MS
authors.lastname: Levy
mesh_terms: D016118:Anterior Cruciate Ligament / Q000601:surgery*; D000070598:Anterior Cruciate Ligament Injuries / Q000601:surgery; D059549:Anterior Cruciate Ligament Reconstruction / Q000379:methods*; D001696:Biomechanical Phenomena; D002102:Cadaver; D006801:Humans; D007593:Joint Instability / Q000601:surgery; D007719:Knee Joint / Q000601:surgery*; D008875:Middle Aged; D016059:Range of Motion, Articular; D012371:Robotics; D012399:Rotation; D013977:Tibia / Q000601:surgery; D019415:Torque; D019737:Transplants
keywords: ACL reconstruction; ALL reconstruction; pivot-shift; tibiofemoral compartment translations