title: Three-Dimensional Analysis of Fibular Motion After Fixation of Syndesmotic Injuries With a Screw or Suture-Button Construct.
abstract: BACKGROUND
  Suture-button constructs are an alternative to screw fixation for syndesmotic injuries, and proponents advocate that suture-button constructs may allow physiological motion of the syndesmosis. Recent biomechanical data suggest that fibular instability with syndesmotic injuries is greatest in the sagittal plane, but the design of a suture-button construct, being a rope and 2 retention washers, is most effective along the axis of the rope (in the coronal plane). Some studies report that suture-button constructs are able to constrain fibular motion in the coronal plane, but the ability of a tightrope to constrain sagittal fibular motion is unknown. The purpose of this study was to assess fibular motion in response to an external rotation stress test in a syndesmotic injury model after fixation with a screw or suture-button constructs.
  
  
  METHODS
  Eleven fresh-frozen cadaver whole legs with intact tibia-fibula articulations were secured to a custom fixture. Fibular motion (coronal, sagittal, and rotational planes) in response to a 6.5-Nm external rotation moment applied to the foot was recorded with fluoroscopy and a high-resolution motion capture system. Measures were taken for the following syndesmotic conditions: intact, complete lateral injury, complete lateral and deltoid injury, repair with a tetracortical 4.0-mm screw, and repair with a suture button construct (Tightrope; Arthrex, Naples, FL) aimed from the lateral fibula to the anterior medial malleolus.
  
  
  RESULTS
  The suture-button construct allowed significantly more sagittal plane motion than the syndesmotic screw. Measurements acquired with mortise imaging did not detect differences between the intact, lateral injury, and 2 repair conditions. External rotation of the fibula was significantly increased in both injury conditions and was not restored to intact levels with the screw or the suture-button construct.
  
  
  CONCLUSIONS
  A single suture-button placed from the lateral fibula to the anterior medial malleolus was unable to replicate the motion observed in the intact specimen when subjected to an external rotation stress test and allowed significantly more posterior motion of the fibula than when fixed with a screw in simulated highly unstable injuries.
  
  
  CONCLUSIONS
  Fixation of a syndesmotic injury with a single suture-button construct did not restore physiological fibular motion, which may have implications for postoperative care and clinical outcomes.
authors.affiliation: University of Calgary, Section of Orthopaedic Surgery, Health Sciences Centre, Calgary, AB, Canada jeremymlamothe@gmail.com.
authors.forename: Jeremy M
authors.initials: JM
authors.lastname: LaMothe
authors.affiliation: Human Motion Lab, Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA, USA.
authors.forename: Josh R
authors.initials: JR
authors.lastname: Baxter
authors.affiliation: Department of Orthopedic Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA, USA.
authors.forename: Conor
authors.initials: C
authors.lastname: Murphy
authors.affiliation: Department of Biomechanics, Hospital for Special Surgery, New York, NY, USA.
authors.forename: Susannah
authors.initials: S
authors.lastname: Gilbert
authors.affiliation: Hospital for Special Surgery, New York, NY, USA.
authors.forename: Bridget
authors.initials: B
authors.lastname: DeSandis
authors.affiliation: Department of Orthopedic Surgery, Foot and Ankle, Hospital for Special Surgery, New York, NY, USA.
authors.forename: Mark C
authors.initials: MC
authors.lastname: Drakos
mesh_terms: D016512:Ankle Injuries / Q000000981:diagnostic imaging / Q000601:surgery*; D001863:Bone Screws; D005360:Fibula / Q000293:injuries / Q000503:physiopathology* / Q000601:surgery; D006801:Humans; D008023:Ligaments, Articular / Q000293:injuries* / Q000601:surgery; D009142:Musculoskeletal Physiological Phenomena; D013536:Suture Techniques; D013977:Tibia / Q000503:physiopathology / Q000601:surgery
keywords: ankle; injury; screw; suture-button construct; syndesmosis