title: Acromial base fractures after reverse total shoulder arthroplasty: report of five cases.
abstract: BACKGROUND
  Most series of reverse total shoulder arthroplasty (rTSA) have reported acromial fractures, but they have not been shown to alter reported outcomes in most series. We present 5 patients with acromial base fractures where the entire deltoid origin was displaced from its anatomic location.
  
  
  METHODS
  Five patients with acromial base fractures after rTSA were identified and evaluated for functional outcomes and pain relief as well as results of fracture treatment. Three were treated operatively and 3 were treated nonoperatively. One nonoperative treatment eventually required open reduction and internal fixation.
  
  
  RESULTS
  Function was limited after fracture, with average forward elevation of only 43° but which improved to 84° after fracture union. Pain was significant after the fracture (6.8 of 10) and improved with fracture healing (0.8 of 10). Neer Functional Outcome scores after fracture union averaged 62 of 100, consistent with unsatisfactory results.
  
  
  CONCLUSIONS
  Acromial base fractures after rTSA are a painful and disabling complication. The outcomes appear different in this series than in other series describing acromial fractures. This may be a result of the different anatomic location of the fractures. Pain improves with fracture union, but functional returns are unpredictable.
authors.affiliation: Department of Orthopaedic Surgery, University of Minnesota, Minneapolis, MN, USA.
authors.forename: Trevor C
authors.initials: TC
authors.lastname: Wahlquist
authors.forename: Allan F
authors.initials: AF
authors.lastname: Hunt
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Braman
mesh_terms: D000174:Acromion / Q000293:injuries* / Q000601:surgery; D000368:Aged; D000369:Aged, 80 and over; D019643:Arthroplasty, Replacement / Q000009:adverse effects*; D004558:Electric Stimulation; D005260:Female; D005593:Fracture Fixation, Internal; D017102:Fracture Healing; D050723:Fractures, Bone / Q000209:etiology* / Q000628:therapy*; D006801:Humans; D007103:Immobilization; D008297:Male; D009989:Orthotic Devices; D010147:Pain Measurement; D016059:Range of Motion, Articular; D012399:Rotation; D020069:Shoulder Pain / Q000209:etiology