title: Use of three-dimensional fluoroscopy to determine intra-articular screw penetration in proximal humeral fracture model.
abstract: BACKGROUND
  Proximal humeral locking plates have significantly improved the treatment of proximal humeral fractures in recent years; however, they are not devoid of complications. Inadvertent screw penetration into the joint is a well-documented complication. Intraoperative 3-dimensional (3D) imaging may assist in detecting intra-articular implant penetration. This study compared the performance of a standard C-arm fluoroscope with a novel 3D imaging fluoroscope in detecting penetrating implants in a proximal humeral fracture model.
  
  
  METHODS
  Zinc-sprayed proximal humerus sawbones were affixed with a proximal humeral locking plate. Six different constructs were assembled. In each specimen, 1 screw, 2 screws, or no screws were inserted 2-mm proud of the articular surface. Each specimen was imaged with a conventional fluoroscope and a 3D imaging fluoroscope. Overall, 36 image sets were prepared for each modality. These were evaluated by 2 fellowship-trained surgeons for intraobserver and interobserver reliability as well for the accuracy of detecting prominent implants in the 2 imaging methods.
  
  
  RESULTS
  Overall accuracy for observer A was 89.9% compared with 100% for C-arm fluoroscopy and 3D imaging fluoroscopy (P < .01) and for observer B was 91.1% and 100% (P = .01), respectively. The κ values were 0.74 with C-arm fluoroscopy and 1.0 for the 3D imaging fluoroscopy for observer A, and 0.93 and 1.0, respectively, for observer B.
  
  
  CONCLUSIONS
  In a proximal humeral fracture model, C-arm fluoroscopy is a highly accurate imaging modality that can minimize the incidence of penetrating screws into the joint. Further clinical studies are required to establish this modality.
authors.affiliation: Department of Orthopaedics, Hadassah Hebrew University Medical Center, Jerusalem, Israel. Electronic address: yoramweil@gmail.com.
authors.forename: Yoram A
authors.initials: YA
authors.lastname: Weil
authors.affiliation: Department of Orthopaedics, Hadassah Hebrew University Medical Center, Jerusalem, Israel.
authors.forename: Shaul
authors.initials: S
authors.lastname: Beyth
authors.affiliation: Department of Orthopaedics, Hadassah Hebrew University Medical Center, Jerusalem, Israel.
authors.forename: Asala
authors.initials: A
authors.lastname: Abu-Ahmad
authors.affiliation: Department of Orthopaedics, Hadassah Hebrew University Medical Center, Jerusalem, Israel.
authors.forename: Amal
authors.initials: A
authors.lastname: Khoury
authors.affiliation: Department of Orthopaedics, Hadassah Hebrew University Medical Center, Jerusalem, Israel.
authors.forename: Meir
authors.initials: M
authors.lastname: Liebergall
authors.affiliation: Department of Orthopaedics, Hadassah Hebrew University Medical Center, Jerusalem, Israel.
authors.forename: Ori
authors.initials: O
authors.lastname: Safran
mesh_terms: D001860:Bone Plates; D001863:Bone Screws; D005471:Fluoroscopy; D005593:Fracture Fixation, Internal / Q000009:adverse effects* / Q000295:instrumentation; D006801:Humans; D058430:Humeral Head / Q000000981:diagnostic imaging* / Q000601:surgery; D021621:Imaging, Three-Dimensional; D007431:Intraoperative Complications / Q000000981:diagnostic imaging; D008953:Models, Anatomic; D015203:Reproducibility of Results; D012784:Shoulder Fractures / Q000601:surgery*
keywords: Proximal humeral fracture; intra-articular implants; three-dimensional fluoroscopy