title: The Fate of the Fixed Syndesmosis Over Time.
abstract: BACKGROUND
  A prior study demonstrated statistical widening of the syndesmosis within weeks of elective screw removal. However, no information is available as to the radiographic outcomes of screw retention. The aim of this study was to evaluate radiographic syndesmotic widening and talar shift over time in patients treated with syndesmotic screws and to compare screw removal with retention along with other potential risk factors that may have led to tibia-fibula diastasis after weightbearing.
  
  
  METHODS
  One hundred sixty-six skeletally mature patients with ankle fractures and concomitant syndesmotic injuries were treated with syndesmotic reduction and screw fixation. The syndesmosis was evaluated intraoperatively either by a stress test or direct visualization. If the syndesmosis was incompetent, it was reduced and stabilized with syndesmotic screws to maintain reduction. Anteroposterior, mortise, and lateral radiographs at presentation, postoperatively, and at follow-up after weightbearing were evaluated. We measured the medial clear space (MCS), tibia-fibula overlap (OL), and tibia-fibula clear space (CS). Screws that were retained were graded as loose/broken or intact.
  
  
  RESULTS
  The fibula shifted an insignificant amount on postoperative mortise radiographs after elective syndesmotic screw removal at 3 months or more after initial fixation, indicated by a slightly greater CS and lower OL. The MCS did not change from preoperative to postoperative screw removal. There was no change in the radiographic markers from the postoperative to final follow-up images in those whose screws became loose or broken. Likewise, there was no radiographic difference if screws remained intact versus those that were loose or broken.
  
  
  CONCLUSIONS
  In contradistinction to prior work, we found that only very mild widening (0.5 mm) of the tibia-fibula space occurred after weightbearing following syndesmotic fixation. The removal of syndesmotic screws at 3 months resulted in a slightly lower OL (<1 mm) and greater CS (0.5 mm) on mortise radiographs than screw retention even if the retained screws loosened or broke. This was not associated with any talar subluxation, and these differences were not statistically significant. The mortise remained intact whether the syndesmotic screws were removed, were loosened or broken, or remained solid.
  
  
  METHODS
  Level IV, retrospective case series.
authors.affiliation: Boston Medical Center, Boston, MA, USA elisabeth.gennis@bmc.org.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Gennis
authors.affiliation: ProHEALTH Care Associates, Lake Success, NY, USA.
authors.forename: Scott
authors.initials: S
authors.lastname: Koenig
authors.affiliation: Boston University Medical School, Boston, MA, USA.
authors.forename: Deirdre
authors.initials: D
authors.lastname: Rodericks
authors.affiliation: Boston University Medical School, Boston, MA, USA.
authors.forename: Peters
authors.initials: P
authors.lastname: Otlans
authors.affiliation: Boston Medical Center, Boston, MA, USA.
authors.forename: Paul
authors.initials: P
authors.lastname: Tornetta
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D064386:Ankle Fractures / Q000000981:diagnostic imaging / Q000601:surgery*; D000843:Ankle Joint / Q000000981:diagnostic imaging / Q000601:surgery*; D001860:Bone Plates; D001863:Bone Screws / Q000009:adverse effects; D015331:Cohort Studies; D020878:Device Removal / Q000706:statistics & numerical data; D005260:Female; D005500:Follow-Up Studies; D005593:Fracture Fixation, Internal / Q000009:adverse effects / Q000295:instrumentation* / Q000379:methods; D017102:Fracture Healing / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011859:Radiography; D016059:Range of Motion, Articular / Q000502:physiology*; D020127:Recovery of Function; D012044:Regression Analysis; D012189:Retrospective Studies; D013997:Time Factors; D016896:Treatment Outcome; D055815:Young Adult
keywords: ankle fracture; screw removal; syndesmosis