title: Conversions from anatomic shoulder replacements to reverse total shoulder arthroplasty: do the indications for initial surgery influence the clinical outcome after revision surgery?
abstract: BACKGROUND
  The most frequent indications for anatomic shoulder replacement are glenohumeral osteoarthritis and fractures of the humeral head. If anatomic shoulder prostheses fail, reverse total shoulder arthroplasty is often the only remaining treatment option. This study evaluates the influence of indications for primary shoulder arthroplasty on the clinical outcome after conversion to reverse total shoulder arthroplasty.
  
  
  METHODS
  From 2010 to 2012, 44 failed shoulder arthroplasties were converted to reverse total shoulder arthroplasty. Forty-four patients were available for follow-up after a mean of 24 months (14-36 months). Twenty-three of them had received an initial shoulder replacement because of osteoarthritis, while the remaining 21 patients had been treated for a fracture of the humeral head. At follow-up, patients were assessed with X-rays, constant-, and ASES scores.
  
  
  RESULTS
  The total number of observed complications was higher in patients revised because of failed fracture arthroplasty (24 vs. 9%). Patients initially treated for osteoarthritis achieved a higher ASES score (71 vs. 59 points; p = 0.048). The normalized constant score was not different between the two observed groups (osteoarthritis 73% vs. fracture 67%: p = 0.45). Complications occurred more often in patients who had initially suffered from a fracture of the humeral head (fracture 23.8% vs. osteoarthritis 8.7%). Scapular notching was more frequent after initial fracture arthroplasty (33 vs. 14%).
  
  
  CONCLUSIONS
  Indications for initial shoulder replacement have an influence on the clinical outcome after conversion to reverse total shoulder arthroplasty. Patients initially treated for a fracture of the humeral head have a lower subjective outcome and a higher complication rate in comparison with patients initially treated for osteoarthritis.
  
  
  METHODS
  IV (Retrospective study).
authors.affiliation: Orthopedic Practice Clinic (OPPK), Schürbusch 55, 48143, Münster, Germany. holmal@web.de.
authors.forename: Malte
authors.identifier: http://orcid.org/0000-0002-7293-2224
authors.initials: M
authors.lastname: Holschen
authors.affiliation: Orthopedic Practice Clinic (OPPK), Schürbusch 55, 48143, Münster, Germany.
authors.forename: Bastian
authors.initials: B
authors.lastname: Franetzki
authors.affiliation: Orthopedic Practice Clinic (OPPK), Schürbusch 55, 48143, Münster, Germany.
authors.forename: Kai-Axel
authors.initials: KA
authors.lastname: Witt
authors.affiliation: Orthopedic Department of the University of Münster, Münster, Germany.
authors.forename: Dennis
authors.initials: D
authors.lastname: Liem
authors.affiliation: Orthopedic Practice Clinic (OPPK), Schürbusch 55, 48143, Münster, Germany.
authors.forename: Jörn
authors.initials: J
authors.lastname: Steinbeck
mesh_terms: D000368:Aged; D000072228:Arthroplasty, Replacement, Shoulder / Q000379:methods*; D005260:Female; D050723:Fractures, Bone / Q000175:diagnosis / Q000601:surgery*; D006801:Humans; D058430:Humeral Head / Q000601:surgery*; D008297:Male; D010003:Osteoarthritis / Q000175:diagnosis / Q000601:surgery*; D011859:Radiography; D012086:Reoperation; D012189:Retrospective Studies; D012540:Scapula / Q000601:surgery*; D012785:Shoulder Joint / Q000000981:diagnostic imaging / Q000601:surgery*; D016896:Treatment Outcome
keywords: Aseptic loosening; Failed shoulder arthroplasty; Osteoarthritis; Proximal humerus fracture; Reverse total shoulder arthroplasty; Revision shoulder arthroplasty; Rotator cuff insufficiency; Scapular notching