title: Syndesmosis fixation: a comparison of three and four cortices of screw fixation without hardware removal.
abstract: BACKGROUND
  Great variability exists in methods of stabilization for syndesmotic disruptions of the ankle. We hypothesized that syndesmotic screw fixation with 3.5-mm fully threaded cortical screws through either three or four cortices would have similar strength and rate of mechanical failure and that retention of screws after fracture healing would not result in adverse clinical symptoms.
  
  
  METHODS
  In a prospective, surgeon-randomized study at a Level-one trauma center, 127 patients with syndesmotic disruptions were treated surgically. Seven patients were lost to followup, leaving 120 for review. Syndesmotic disruptions were stabilized with 3.5-mm fully threaded cortical screws placed through three or four cortices. Screws were removed only if symptomatic. Outcome criteria were screw failure, loss of reduction, and need for hardware removal.
  
  
  RESULTS
  Fifty-nine patients received fixation through three cortices and 61 patients received fixation through four cortices. Mean follow-up was 150 days. In the group with stabilization through three cortices, hardware failure occurred in five patients (8%) and three had a loss of reduction. In the group with stabilization through four cortices, hardware failure occurred in four patients (7%); all were asymptomatic and did not require screw removal. There was no loss of reduction in that group. Comparing the two groups using binary logistic analysis, there was no difference in loss of reduction (p = 0.871), screw breakage (p = 0.689), or need for hardware removal (p = 0.731).
  
  
  CONCLUSIONS
  The data suggest that either three or four cortices of fixation can be used when stabilizing syndesmotic injuries of the ankle. There was a trend towards higher loss of reduction in the group with tricortical fixation when weightbearing restrictions were not followed. Retention of the syndesmotic screws, even with mechanical failure, does not pose a clinical problem. Weightbearing can be allowed at 6 to 10 weeks without routine removal of screws.
authors.affiliation: The Orthopaedic and Neurosurgical Center of the Cascades, 2200 NE Neff Road, Suite 200, Bend, Oregon 97701, USA. jmoore@neuroortho.com
authors.forename: Joel A
authors.initials: JA
authors.lastname: Moore
authors.forename: John R
authors.initials: JR
authors.lastname: Shank
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Morgan
authors.forename: Wade R
authors.initials: WR
authors.lastname: Smith
mesh_terms: D000328:Adult; D016512:Ankle Injuries / Q000000981:diagnostic imaging / Q000601:surgery*; D001863:Bone Screws; D002370:Casts, Surgical; D003627:Data Interpretation, Statistical; D005260:Female; D005360:Fibula / Q000293:injuries*; D005471:Fluoroscopy; D005500:Follow-Up Studies; D005593:Fracture Fixation, Internal / Q000295:instrumentation / Q000379:methods*; D017102:Fracture Healing; D050723:Fractures, Bone / Q000601:surgery*; D006801:Humans; D007103:Immobilization; D008297:Male; D011446:Prospective Studies; D013997:Time Factors; D016896:Treatment Outcome