title: Computer-Assisted 3-Dimensional Reconstructions of Scaphoid Fractures and Nonunions With and Without the Use of Patient-Specific Guides: Early Clinical Outcomes and Postoperative Assessments of Reconstruction Accuracy.
abstract: OBJECTIVE
  To present results regarding the accuracy of the reduction of surgically reconstructed scaphoid nonunions or fractures using 3-dimensional computer-based planning with and without patient-specific guides.
  
  
  METHODS
  Computer-based surgical planning was performed with computed tomography (CT) data on 22 patients comparing models of the pathological and the opposite uninjured scaphoid in 3 dimensions. For group 1 (9 patients), patient-specific guides were designed and manufactured using additive manufacturing technology. During surgery, the guides were used to define the orientation of the reduced fragments. The scaphoids in group 2 (13 patients) were reduced with the conventional freehand technique. All scaphoids in both groups were fixed with a headless compression screw or K-wires, and all bone defects (except one) were filled with autologous bone grafts or vascularized grafts. Postoperative CT scans were acquired 2 or more months after the operations to monitor consolidation and compare the final result with the preoperative plan. The clinical results and accuracy of the reconstructions were compared.
  
  
  RESULTS
  In group 1, 8 of 9 scaphoids healed after 2 to 6 months, and partial nonunion after 9 months was observed in one patient. In group 2, 11 of 13 scaphoids healed between 2 and 34 months whereas 2 scaphoids did not consolidate. Comparison of the preoperative and postoperative 3-dimensional data revealed an average residual displacement of 7° (4° in flexion-extension, 4° in ulnar-radial deviation, and 3° in pronation-supination) in group 1. In group 2, residual displacement after surgery was 26° (22° in flexion-extension, 12° in ulnar-radial deviation, and 7° in pronation-supination). The difference in the accuracy of reconstruction was significant.
  
  
  CONCLUSIONS
  Although the scaphoid is small, patient-specific guides can be used to perform scaphoid reconstructions. When the guides were used, the reconstructions were significantly more anatomic compared with those resulting from the freehand technique.
  
  
  METHODS
  Therapeutic III.
authors.affiliation: Orthopedic Department, Balgrist University Hospital, University of Zurich, Zurich, Switzerland.
authors.forename: Andreas
authors.initials: A
authors.lastname: Schweizer
authors.affiliation: Orthopedic Department, Balgrist University Hospital, University of Zurich, Zurich, Switzerland.
authors.forename: Flavien
authors.initials: F
authors.lastname: Mauler
authors.affiliation: Computer Assisted Research and Development Group, Balgrist University Hospital, University of Zurich, Zurich, Switzerland.
authors.forename: Lazaros
authors.initials: L
authors.lastname: Vlachopoulos
authors.affiliation: Orthopedic Department, Balgrist University Hospital, University of Zurich, Zurich, Switzerland.
authors.forename: Ladislav
authors.initials: L
authors.lastname: Nagy
authors.affiliation: Computer Assisted Research and Development Group, Balgrist University Hospital, University of Zurich, Zurich, Switzerland. Electronic address: philipp.fuernstahl@card.balgrist.ch.
authors.forename: Philipp
authors.initials: P
authors.lastname: Fürnstahl
mesh_terms: D000293:Adolescent; D000328:Adult; D016025:Bone Transplantation; D003198:Computer Simulation; D005260:Female; D005593:Fracture Fixation, Internal / Q000295:instrumentation*; D017102:Fracture Healing; D050723:Fractures, Bone / Q000000981:diagnostic imaging / Q000601:surgery*; D005599:Fractures, Ununited / Q000000981:diagnostic imaging / Q000601:surgery*; D006801:Humans; D021621:Imaging, Three-Dimensional; D007430:Intraoperative Care / Q000295:instrumentation; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications; D011300:Preoperative Care; D012189:Retrospective Studies; D021361:Scaphoid Bone / Q000000981:diagnostic imaging / Q000293:injuries / Q000601:surgery*; D025321:Surgery, Computer-Assisted; D014057:Tomography, X-Ray Computed; D055815:Young Adult
keywords: Computer-assisted 3-dimensional planning; contralateral side; osteotomy; patient-specific guides; rapid prototyping