title: Predictors of a persistent dislocation after reduction of syndesmotic injuries detected with intraoperative three-dimensional imaging.
abstract: BACKGROUND
  In about 25% of cases, reduction of acute unstable syndesmotic injuries and stabilization with syndesmotic screws leads to an inadequate reduction. Conventional fluoroscopy does not provide reliable information about the reduction outcome. However, use of intraoperative 3D imaging can be more accurate. The purpose of this study was to identify predictors of inadequate reduction so that the need for intra- or postoperative 3D imaging could be assessed. Our hypothesis was that complex injuries of the syndesmosis present a higher risk of malreduction than simpler ankle fractures.
  
  
  METHODS
  From August 2001 to February 2011, 251 unstable syndesmotic injuries were treated from a total of 2286 ankle fractures. In 61 of these cases, malreduction of the fibula into the fibular notch was detected by intraoperative 3D imaging. The influence of all possible concomitant and combination injuries of the ankle joint, surgeon's experience, and potential implant-related effects was analyzed.
  
  
  RESULTS
  Thirty-seven Weber C fractures (60.7%), 13 Maisonneuve fractures (21.3%), 10 Weber B fractures (16.4%), and 1 syndesmotic injury without fracture (1.6%) were included. In 14 cases (23%) there was involvement of the posterior malleolus, in 10 cases of the medial malleolus (16.4%), and in 12 cases both (19.7%). The Weber C fractures included 10 bimalleolar fractures with involvement of the posterior malleolus. In neither this combination nor in any other possible injury configuration was it possible to identify a statistically significant correlation with malreduction of the fibula into the fibular notch. The surgeon's experience or an implant-related effect had no detectable influence either.
  
  
  CONCLUSIONS
  Based on the factors studied, it is not possible to conclude whether a patient has an increased risk of malreduction. Therefore we still recommend verifying all reduction outcomes by intraoperative 3D imaging or postoperative computed tomography.
  
  
  METHODS
  Level III, retrospective comparative study.
authors.affiliation: BG Trauma Center Ludwigshafen at Heidelberg University Hospital, Ludwigshafen, Germany jochen.franke@bgu-ludwigshafen.de.
authors.forename: Jochen
authors.initials: J
authors.lastname: Franke
authors.affiliation: BG Trauma Center Ludwigshafen at Heidelberg University Hospital, Ludwigshafen, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: von Recum
authors.affiliation: BG Trauma Center Ludwigshafen at Heidelberg University Hospital, Ludwigshafen, Germany.
authors.forename: Arnold J
authors.initials: AJ
authors.lastname: Suda
authors.affiliation: BG Trauma Center Ludwigshafen at Heidelberg University Hospital, Ludwigshafen, Germany.
authors.forename: Sven
authors.initials: S
authors.lastname: Vetter
authors.affiliation: BG Trauma Center Ludwigshafen at Heidelberg University Hospital, Ludwigshafen, Germany.
authors.forename: Paul Alfred
authors.initials: PA
authors.lastname: Grützner
authors.affiliation: BG Trauma Center Ludwigshafen at Heidelberg University Hospital, Ludwigshafen, Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Wendl
mesh_terms: D016512:Ankle Injuries / Q000000981:diagnostic imaging* / Q000601:surgery*; D001863:Bone Screws; D002908:Chronic Disease; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D005593:Fracture Fixation, Internal / Q000009:adverse effects / Q000379:methods; D017102:Fracture Healing / Q000502:physiology*; D017759:Fractures, Malunited / Q000000981:diagnostic imaging* / Q000517:prevention & control; D006801:Humans; D021621:Imaging, Three-Dimensional; D015601:Injury Severity Score; D007430:Intraoperative Care / Q000379:methods; D004204:Joint Dislocations / Q000000981:diagnostic imaging / Q000601:surgery*; D008297:Male; D011182:Postoperative Care / Q000379:methods; D011237:Predictive Value of Tests; D016059:Range of Motion, Articular / Q000502:physiology; D020127:Recovery of Function / Q000502:physiology; D012189:Retrospective Studies; D018570:Risk Assessment; D014057:Tomography, X-Ray Computed / Q000379:methods; D016896:Treatment Outcome
keywords: 3-dimensional imaging; ankle fracture; intraoperative 3D imaging; syndesmotic screw; unstable syndesmotic injury