title: Rapid prototyping in the assessment, classification and preoperative planning of acetabular fractures.
abstract: OBJECTIVE
  To evaluate the use of rapid prototyping in the assessment, classification and preoperative planning of acetabular fractures.
  
  
  BACKGROUND
  The complex three-dimensional anatomy of the pelvis and acetabulum make assessment, classification and treatment of fractures of these structures notoriously difficult. Conventional imaging only provides two-dimensional images of these fractures. While interpretation of traditional imaging techniques becomes better with experience, novel techniques may assist in the understanding of these complex injuries.
  
  
  METHODS
  Twenty patients with acetabular fractures were studied. Life size three-dimensional models were manufactured from standardised CT scans, using the rapid prototyping process, selective laser sintering. Each model was presented to the operating surgeon prior to surgery. The surgeons found that the models greatly assisted in their understanding of the personality of the fracture. Three consultant orthopaedic surgeons and three senior trainees were asked to classify each fracture using conventional radiographs (AP pelvis, Judet views and CT scans) and then using the model. The kappa statistic was used to evaluate inter- and intraobserver agreement.
  
  
  RESULTS
  Interobserver agreement was not absolute using either conventional radiographs or the models. For the consultants the kappa statistic using conventional radiographs was 0.61 while the kappa value using the model was 0.76 (p<0.05). For the trainees the kappa value was 0.42, using conventional radiographs and 0.71 using the model (p<0.01).
  
  
  CONCLUSIONS
  Full sized models of acetabular fractures greatly assisted surgeons understand the personality of complex fractures prior to surgery and have been shown in this study to significantly reduced the degree of interobserver variability in fracture classification. This effect is particularly evident for less experienced surgeons. This technique is available and relatively inexpensive. The use of these models should prove invaluable as a tool to aid clinical practice.
authors: The Adelaide and Meath Hospital Incorporating the National Children's Hospital, Talaght, Dublin, Ireland. conorhurson@hotmail.com
authors: C
authors: C
authors: Hurson
authors: A
authors: A
authors: Tansey
authors: B
authors: B
authors: O'Donnchadha
authors: P
authors: P
authors: Nicholson
authors: J
authors: J
authors: Rice
authors: J
authors: J
authors: McElwain
mesh_terms: D000077:Acetabulum / Q000000981:diagnostic imaging / Q000293:injuries*; D002983:Clinical Competence / Q000706:statistics & numerical data; D050723:Fractures, Bone / Q000175:diagnosis* / Q000000981:diagnostic imaging; D006801:Humans; D008953:Models, Anatomic; D015588:Observer Variation; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed