title: Decreased scapular notching with lateralization and inferior baseplate placement in reverse shoulder arthroplasty with high humeral inclination.
abstract: BACKGROUND
  Scapular notching is a radiographic finding of unknown clinical significance following reverse total shoulder arthroplasty (RTSA). The purpose of this study was to determine how baseplate position affects the incidence of scapular notching and measure the clinical outcomes.
  
  
  OBJECTIVE
  We hypothesized that low base plate position on the glenoid and new prosthesis design with a higher humeral inclination angle would decrease the incidence of notching at 2 years follow-up.
  
  
  METHODS
  A total of 54 patients with an average follow-up of 30 months met inclusion criteria and underwent radiographic analysis of scapular notching and radiographic measures to determine glenoid component placement. Clinical measures including visual analog score, American Shoulder and Elbow Surgeons (ASES) scores, and range of motion (ROM) were prospectively collected.
  
  
  RESULTS
  Thirty-nine of the 54 patients had no notching. 7 had Grade 1 notching, 7 had Grade 2 notching, one had Grade 3, and one had Grade 4 notching. Notching was associated with higher placement of the glenoid component as measured by peg-glenoid rim distance and base plate distance. All patients with no evidence of notching at 1-year, continued to have no notching after multi-year follow-up. Clinical outcome measures including ASES scores, ROM, and visual analog pain scores were improved at follow-up.
  
  
  CONCLUSIONS
  We concluded that lower neck-shaft angle and low baseplate positioning led to a low incidence of significant scapular notching as only 6 out of 57 (16%) patients had notching Grade 2 and above. At short-term follow-up, this RTSA results in excellent clinical outcomes and a significantly lower scapular notching rate than traditional techniques.
authors.affiliation: Department of Orthopaedic Surgery, University of California, San Francisco, CA, USA.
authors.forename: Brian T
authors.initials: BT
authors.lastname: Feeley
authors.affiliation: Department of Orthopaedic Surgery, University of California, San Francisco, CA, USA.
authors.forename: Alan L
authors.initials: AL
authors.lastname: Zhang
authors.affiliation: Department of Orthopaedic Surgery, University of California, San Francisco, CA, USA.
authors.forename: Jeffery J
authors.initials: JJ
authors.lastname: Barry
authors.affiliation: Department of Orthopaedic Surgery, University of California, San Francisco, CA, USA.
authors.forename: Edward
authors.initials: E
authors.lastname: Shin
authors.affiliation: Department of Orthopaedic Surgery, University of California, San Francisco, CA, USA.
authors.forename: Julianne
authors.initials: J
authors.lastname: Ho
authors.affiliation: Department of Orthopaedic Surgery, University of California, San Francisco, CA, USA.
authors.forename: Ehsan
authors.initials: E
authors.lastname: Tabaraee
authors.affiliation: Department of Orthopaedic Surgery, University of California, San Francisco, CA, USA.
authors.forename: C Benjamin
authors.initials: CB
authors.lastname: Ma
keywords: Reverse shoulder arthroplasty; rotator cuff arthropathy; scapular notching