title: Effect of Intraoperative Three-Dimensional Imaging During the Reduction and Fixation of Displaced Calcaneal Fractures on Articular Congruence and Implant Fixation.
abstract: BACKGROUND
  Operative treatment of displaced calcaneal fractures should restore joint congruence, but conventional fluoroscopy is unable to fully visualize the subtalar joint. We questioned whether intraoperative 3-dimensional (3D) imaging would aid in the reduction of calcaneal fractures, resulting in improved articular congruence and implant positioning.
  
  
  METHODS
  Sixty-two displaced calcaneal fractures were operated on using standard fluoroscopic views. When the surgeon had achieved a satisfactory reduction, an intraoperative 3D scan was conducted, malreductions or implant imperfections were revised, the calcaneus was rescanned, and this sequence was repeated until the optimal operative result was achieved.
  
  
  RESULTS
  Five fractures underwent 1 intraoperative scan, 39 fractures underwent 2 scans, 13 fractures underwent 3 scans, and 5 fractures underwent 4 scans. The average number of scans was 2.3. Intraoperative scanning led to re-reduction and improvement of reduction in 13 fractures, change of plate position in 1 patient, optimizing of the screw directions in 5 fractures, and shortening of screws that were intra-articular or protruding medially in 6 fractures. The postoperative articular displacement was 0 mm in 69% of the Sanders type 2 fractures and 57% of the Sanders type 3 fractures. Operation duration averaged 118 minutes, and there were no reoperations due to misplaced screws or plates. The average absorbed radiation dose per patient was 288 mGy·cm.
  
  
  CONCLUSIONS
  Intraoperative 3D imaging improved the articular reduction of the posterior facet and secured optimal implant position in displaced calcaneal fractures. Radiation dose to the patient was less than that of a normal foot computed tomography scan.
  
  
  METHODS
  Level IV, case series.
authors.affiliation: Department of Traumatology, Basel University Hospital, Basel, Switzerland henrikeckardt@gmail.com.
authors.forename: Henrik
authors.initials: H
authors.lastname: Eckardt
authors.affiliation: Department of Orthopaedic Traumatology, Copenhagen University Hospital Rigshospitalet, Copenhagen, Denmark.
authors.forename: Marianne
authors.initials: M
authors.lastname: Lind
mesh_terms: D000328:Adult; D000368:Aged; D002111:Calcaneus / Q000293:injuries* / Q000601:surgery; D005260:Female; D005471:Fluoroscopy; D005593:Fracture Fixation, Internal / Q000379:methods*; D050723:Fractures, Bone / Q000000981:diagnostic imaging / Q000601:surgery*; D006801:Humans; D021621:Imaging, Three-Dimensional; D007432:Intraoperative Period; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013380:Subtalar Joint / Q000000981:diagnostic imaging / Q000473:pathology*; D014057:Tomography, X-Ray Computed; D055815:Young Adult
keywords: Böhler angle; Sanders classification; displaced calcaneal fracture; fluoroscopy; intraoperative 3-dimensional imaging; intraoperative control of reduction; open reduction and internal fixation