title: A complication-based learning curve from 200 reverse shoulder arthroplasties.
abstract: BACKGROUND
  Reported early complication rates in reverse total shoulder arthroplasty have widely varied from 0% to 75% in part due to a lack of standard inclusion criteria. In addition, it is unclear whether revision arthroplasty is associated with a higher rate of complications than primary arthroplasty.
  
  
  OBJECTIVE
  We therefore (1) determined the types and rates of early complications in reverse total shoulder arthroplasty using defined criteria, (2) characterized an early complication-based learning curve for reverse total shoulder arthroplasty, and (3) determined whether revision arthroplasties result in a higher incidence of complications.
  
  
  METHODS
  From October 2004 to May 2008, an initial series of 200 reverse total shoulder arthroplasties was performed in 191 patients by a single surgeon. Forty of the 200 arthroplasties were revision arthroplasties. Of these, 192 shoulders were available for minimum 6-month followup (mean, 19.4 months; range, 6-49.2 months). We determined local and systemic complications and distinguished major from minor complications.
  
  
  RESULTS
  Nineteen shoulders involved local complications (9.9%), including seven major and 12 minor complications. Nine involved perioperative systemic complications (4.7%), including eight major complications and one minor complication. The local complication rate was higher in the first 40 shoulders (23.1%) versus the last 160 shoulders (6.5%). Seven of 40 (17.5%) revision arthroplasties involved local complications, including two major and five minor complications compared to 12 of 152 (7.9%) primary arthroplasties, including five major and seven minor complications. Nerve palsies occurred less frequently in primary arthroplasties (0.6%) compared to revisions (9.8%).
  
  
  CONCLUSIONS
  The early complication-based learning curve for reverse total shoulder arthroplasty is approximately 40 cases. There was a trend toward more complications in revision versus primary reverse total shoulder arthroplasty and more neuropathies in revisions.
  
  
  METHODS
  Level IV, therapeutic study. See the guidelines online for a complete description of level of evidence.
authors.affiliation: Department of Orthopaedic Surgery, William Beaumont Hospital, 3535 West Thirteen Mile Road Ste 744, Royal Oak, MI 48073, USA.
authors.forename: Laurence B
authors.initials: LB
authors.lastname: Kempton
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Ankerson
authors.forename: J Michael
authors.initials: JM
authors.lastname: Wiater
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019643:Arthroplasty, Replacement / Q000009:adverse effects* / Q000295:instrumentation; D001696:Biomechanical Phenomena; D016009:Chi-Square Distribution; D002983:Clinical Competence; D005260:Female; D006801:Humans; D007595:Joint Prosthesis; D059032:Learning Curve; D008297:Male; D008824:Michigan; D008875:Middle Aged; D016017:Odds Ratio; D011183:Postoperative Complications / Q000517:prevention & control*; D011474:Prosthesis Design; D011859:Radiography; D012042:Registries; D012086:Reoperation; D018570:Risk Assessment; D012307:Risk Factors; D012785:Shoulder Joint / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000601:surgery*; D013997:Time Factors; D016896:Treatment Outcome