title: Anatomic Ligament Repair Restores Ankle and Syndesmotic Rotational Stability as Much as Syndesmotic Screw Fixation.
abstract: OBJECTIVE
  To compare the external rotation stability of 3 different syndesmotic stabilization techniques in a cadaveric ankle fracture model.
  
  
  METHODS
  Nondestructive external rotation stresses of 4 N·m were applied to 8 cadaveric limbs using a hydraulic loading frame. Four conditions were tested using a repeated-measures design: intact and 3 repair conditions after a destabilizing ligamentous ankle injury with syndesmotic disruption. The 3 repair conditions were tricortical trans-syndesmotic screw fixation, posterior inferior tibiofibular ligament (PITFL) repair, and combined PITFL and deltoid ligament repair. External rotation of the ankle joint and syndesmosis was measured using a motion capture system and compared for each test condition. Repeated-measures 1-way analyses of variance statistical tests were performed to compare the ankle and syndesmotic rotation findings between the 3 repair conditions and intact condition.
  
  
  RESULTS
  Rotational ankle stability was not fully restored by any of the 3 repair constructs. The intact ankle joint externally rotated approximately half as many degrees as the 3 repair conditions (intact: 10.9; trans-syndesmotic screw: 17.0; PITFL: 21.4; and PITFL/deltoid: 15.6). The intact condition also demonstrated significantly fewer degrees of syndesmotic rotation than the repair constructs (intact 2.4; trans-syndesmotic screw 5.2; PITFL 8.5; and PITFL/deltoid 6.9). Each of the repair conditions resulted in an externally rotated fibula when no loads were applied. The ligamentous repairs externally rotated the fibula twice as much as the trans-syndesmotic screw (P < 0.016).
  
  
  CONCLUSIONS
  We found that combined repair of the PITFL and deltoid ligament restores an equivalent amount of ankle and syndesmotic rotational stability when compared to trans-syndesmotic screw fixation. Based on our findings, ligamentous repair can potentially be a viable treatment alternative in unstable ankle fracture patients with syndesmotic disruption.
  
  
  METHODS
  Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.
authors: *Department of Orthopaedics and Rehabilitation, University of Vermont College of Medicine, Burlington, VT;†Department of Biomechanics, Hospital for Special Surgery, New York, NY;‡Department of Orthopaedics and Sports Medicine, University of Washington, Seattle, WA; and§Department of Orthopaedic Surgery, Hospital for Special Surgery and New York Presbyterian Hospital, New York, NY.
authors: Patrick C
authors: PC
authors: Schottel
authors: Josh
authors: J
authors: Baxter
authors: Susannah
authors: S
authors: Gilbert
authors: Matthew R
authors: MR
authors: Garner
authors: Dean G
authors: DG
authors: Lorich
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D064386:Ankle Fractures / Q000175:diagnosis / Q000601:surgery*; D001863:Bone Screws; D002102:Cadaver; D005260:Female; D005593:Fracture Fixation, Internal / Q000295:instrumentation* / Q000379:methods; D017102:Fracture Healing; D006801:Humans; D007593:Joint Instability / Q000175:diagnosis / Q000601:surgery*; D017844:Lateral Ligament, Ankle / Q000293:injuries* / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D016059:Range of Motion, Articular; D016896:Treatment Outcome