title: Patient-specific targeting guides compared with traditional instrumentation for glenoid component placement in shoulder arthroplasty: a multi-surgeon study in 70 arthritic cadaver specimens.
abstract: OBJECTIVE
  The purpose of this study was to compare the accuracy of patient-specific guides for total shoulder arthroplasty (TSA) with traditional instrumentation in arthritic cadaver shoulders. We hypothesized that the patient-specific guides would place components more accurately than standard instrumentation.
  
  
  METHODS
  Seventy cadaver shoulders with radiographically confirmed arthritis were randomized in equal groups to 5 surgeons of varying experience levels who were not involved in development of the patient-specific guidance system. Specimens were then randomized to patient-specific guides based off of computed tomography scanning, standard instrumentation, and anatomic TSA or reverse TSA. Variances in version or inclination of more than 10° and more than 4 mm in starting point were considered indications of significant component malposition.
  
  
  RESULTS
  TSA glenoid components placed with patient-specific guides averaged 5° of deviation from the intended position in version and 3° in inclination; those with standard instrumentation averaged 8° of deviation in version and 7° in inclination. These differences were significant for version (P = .04) and inclination (P = .01). Multivariate analysis of variance to compare the overall accuracy for the entire cohort (TSA and reverse TSA) revealed patient-specific guides to be significantly more accurate (P = .01) for the combined vectors of version and inclination. Patient-specific guides also had fewer instances of significant component malposition than standard instrumentation did.
  
  
  CONCLUSIONS
  Patient-specific targeting guides were more accurate than traditional instrumentation and had fewer instances of component malposition for glenoid component placement in this multi-surgeon cadaver study of arthritic shoulders. Long-term clinical studies are needed to determine if these improvements produce improved functional outcomes.
authors.affiliation: Department of Orthopaedic Surgery and Biomedical Engineering, University of Tennessee-Campbell Clinic, Memphis, TN, USA. Electronic address: tthrockmorton@campbellclinic.com.
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Throckmorton
authors.affiliation: Department of Orthopaedic Surgery, Hospital for Special Surgery, Weill Cornell Medical College, New York, NY, USA.
authors.forename: Lawrence V
authors.initials: LV
authors.lastname: Gulotta
authors.affiliation: Department of Orthopaedic Surgery, University of Louisville, Louisville, KT, USA.
authors.forename: Frank O
authors.initials: FO
authors.lastname: Bonnarens
authors.affiliation: SportONE, Ortho NorthEast, Fort Wayne, IN, USA.
authors.forename: Stephen A
authors.initials: SA
authors.lastname: Wright
authors.affiliation: Wabash Orthopaedic Center, Wabash, IN, USA.
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Hartzell
authors.affiliation: South Bend Orthopaedics, South Bend, IN, USA.
authors.forename: William B
authors.initials: WB
authors.lastname: Rozzi
authors.affiliation: Joint Implant Surgeons, Inc., New Albany, OH, USA.
authors.forename: Jason M
authors.initials: JM
authors.lastname: Hurst
authors.affiliation: Department of Orthopaedic Surgery, University of Liverpool, Liverpool, UK.
authors.forename: Simon P
authors.initials: SP
authors.lastname: Frostick
authors.affiliation: Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, USA.
authors.forename: John W
authors.initials: JW
authors.lastname: Sperling
mesh_terms: D001168:Arthritis / Q000000981:diagnostic imaging / Q000601:surgery*; D019643:Arthroplasty, Replacement / Q000295:instrumentation / Q000379:methods*; D002102:Cadaver; D061165:Glenoid Cavity / Q000000981:diagnostic imaging; D006801:Humans; D021621:Imaging, Three-Dimensional; D011859:Radiography; D012785:Shoulder Joint / Q000000981:diagnostic imaging / Q000601:surgery*; D015898:Tomography Scanners, X-Ray Computed
keywords: Total shoulder arthroplasty; cadaver study; component placement; patient-specific targeting guides; standard guides