title: Three-dimensional preoperative planning software and a novel information transfer technology improve glenoid component positioning.
abstract: BACKGROUND
  We hypothesized that a novel surgical method, in which three-dimensional (3-D) preoperative planning software is generated to create a patient-specific surgical model that is used with a reusable and adjustable tool, could substantially improve the positioning accuracy of the glenoid guide pin used in total shoulder arthroplasty. We tested this method using bone models from patients with shoulder pathology and compared the results with those achieved using surgical methods representing the current standard of care.
  
  
  METHODS
  Three surgeons with a variety of surgical experience placed a guide pin in nine bone models from patients with a variety of glenohumeral arthritis severity using (1) standard instrumentation alone, (2) standard instrumentation and 3-D preoperative surgical planning, and (3) the reusable transfer device and 3-D preoperative surgical planning. A postoperative 3-D computed tomography scan of the bone model was made and registered to the preoperative plan, and the differences between the actual and planned pin locations and trajectories were measured.
  
  
  RESULTS
  Use of the standard instrumentation combined with 3-D preoperative planning software improved guide pin positioning compared with standard instrumentation and preoperative planning using 2-D imaging. The accuracy of pin positioning increased by 4.5° ± 1.0° in version (p &lt; 0.001), 3.3° ± 1.3° in inclination (p = 0.013), and 0.4 ± 0.2 mm in location (p = 0.042). Use of the adjustable and reusable device and the 3-D software improved pin positioning by a further 3.7° ± 0.9° in version, 8.1° ± 1.2° in inclination, and 1.2 ± 0.2 mm in location (p &lt; 0.001 for all) compared with standard instrumentation and the 3-D software; the improvement compared with use of standard instrumentation with 2-D imaging was 8.2° ± 0.9° in version, 11.4° ± 1.2° in inclination, and 1.7 ± 0.2 mm in location (p &lt; 0.001 for all).
  
  
  CONCLUSIONS
  Use of 3-D preoperative planning and use of the patient-specific bone model and transfer device both improved the positioning accuracy of the pin used to guide placement of the glenoid component in total shoulder arthroplasty.
  
  
  CONCLUSIONS
  Proper positioning of the glenoid component would be expected to improve the function and durability of the joint replacement.
authors.affiliation: Department of Orthopaedic Surgery, Cleveland Clinic, 9500 Euclid Avenue, A-41, Cleveland, OH 44195. E-mail address for J. Iannotti: iannotj@ccf.org.
authors.forename: Joseph
authors.initials: J
authors.lastname: Iannotti
authors.affiliation: Custom Orthopaedic Solutions, 10000 Cedar Avenue, Cleveland, OH 44106.
authors.forename: Justin
authors.initials: J
authors.lastname: Baker
authors.affiliation: Department of Orthopaedic Surgery, Cleveland Clinic, 9500 Euclid Avenue, A-41, Cleveland, OH 44195. E-mail address for J. Iannotti: iannotj@ccf.org.
authors.forename: Eric
authors.initials: E
authors.lastname: Rodriguez
authors.affiliation: Department of Orthopaedic Surgery, Cleveland Clinic, 9500 Euclid Avenue, A-41, Cleveland, OH 44195. E-mail address for J. Iannotti: iannotj@ccf.org.
authors.forename: John
authors.initials: J
authors.lastname: Brems
authors.affiliation: Department of Orthopaedic Surgery, Cleveland Clinic, 9500 Euclid Avenue, A-41, Cleveland, OH 44195. E-mail address for J. Iannotti: iannotj@ccf.org.
authors.forename: Eric
authors.initials: E
authors.lastname: Ricchetti
authors.affiliation: Department of Orthopaedic Surgery, Cleveland Clinic, 9500 Euclid Avenue, A-41, Cleveland, OH 44195. E-mail address for J. Iannotti: iannotj@ccf.org.
authors.forename: Mena
authors.initials: M
authors.lastname: Mesiha
authors.affiliation: Image IQ, 10000 Cedar Avenue, Cleveland, OH 44106.
authors.forename: Jason
authors.initials: J
authors.lastname: Bryan
mesh_terms: D019643:Arthroplasty, Replacement / Q000379:methods*; D001858:Bone Nails; D003198:Computer Simulation; D061165:Glenoid Cavity / Q000601:surgery*; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods; D008490:Medical Informatics; D008953:Models, Anatomic; D010347:Patient Care Planning; D011300:Preoperative Care / Q000379:methods; D012044:Regression Analysis; D012785:Shoulder Joint / Q000601:surgery*; D012984:Software; D025321:Surgery, Computer-Assisted / Q000379:methods; D014057:Tomography, X-Ray Computed