title: Outcome of Revision Shoulder Arthroplasty After Resurfacing Hemiarthroplasty in Patients with Glenohumeral Osteoarthritis.
abstract: BACKGROUND
  Patients are often treated with a resurfacing hemiarthroplasty in the expectation that the bone-preserving design facilitates revision should the need for a revision arthroplasty arise. The aim of this study was to report the outcome of patients with glenohumeral osteoarthritis who underwent revision shoulder arthroplasty after resurfacing hemiarthroplasty.
  
  
  METHODS
  We reviewed all patients with osteoarthritis reported to the Danish Shoulder Arthroplasty Registry from 2006 to 2013. There were 1,210 primary resurfacing hemiarthroplasties, of which 107 cases (9%) required a revision surgical procedure, defined as the removal or exchange of the humeral component or the addition of a glenoid component. The Western Ontario Osteoarthritis of the Shoulder (WOOS) index was used to evaluate outcome at 1 year.
  
  
  RESULTS
  The median WOOS of revision arthroplasty after failed resurfacing hemiarthroplasty was 62 points (interquartile range, 40 to 88 points). Of the 80 cases that had follow-up, 33 (41%) had an unacceptable outcome, defined as a WOOS of ≤50 points. Of the 107 cases that required a revision surgical procedure, 11 arthroplasties (10%) required a further revision surgical procedure. The resurfacing hemiarthroplasty was revised to a stemmed hemiarthroplasty (n = 39), anatomic total shoulder arthroplasty (n = 31), or reverse shoulder arthroplasty (n = 30). In 7 cases, the revision arthroplasty design was unknown. The median WOOS of patients who underwent revision stemmed hemiarthroplasty (48 points) was significantly inferior (p = 0.002) to that of patients who underwent primary stemmed hemiarthroplasty (75 points); the median WOOS of patients who underwent revision anatomic total shoulder arthroplasty (74 points) was also significantly inferior (p = 0.007) to that of patients who underwent primary anatomic total shoulder arthroplasty (93 points). However, the median WOOS of patients who underwent revision reverse shoulder arthroplasty (68 points) was not significantly different (p = 0.66) from that of patients who underwent primary reverse shoulder arthroplasty (77 points) used in the treatment of osteoarthritis.
  
  
  CONCLUSIONS
  The outcome of revision shoulder arthroplasty after failed resurfacing hemiarthroplasty was variable and, in many cases, disappointing. It is important that resurfacing hemiarthroplasty is used for the correct indications and with adequate technique and skill. When resurfacing hemiarthroplasty is used in the treatment of osteoarthritis, revision cannot be counted upon as a fallback.
  
  
  METHODS
  Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.
authors.affiliation: Department of Orthopaedic Surgery, Herlev University Hospital, Herlev, Denmark jevera01@heh.regionh.dk.
authors.forename: Jeppe V
authors.initials: JV
authors.lastname: Rasmussen
authors.affiliation: Department of Orthopaedic Surgery, Herlev University Hospital, Herlev, Denmark.
authors.forename: Bo S
authors.initials: BS
authors.lastname: Olsen
authors.affiliation: Department of Orthopaedic Surgery, Herlev University Hospital, Herlev, Denmark.
authors.forename: Ali
authors.initials: A
authors.lastname: Al-Hamdani
authors.affiliation: Department of Orthopaedic Surgery, Herlev University Hospital, Herlev, Denmark.
authors.forename: Stig
authors.initials: S
authors.lastname: Brorson
mesh_terms: D000368:Aged; D000072228:Arthroplasty, Replacement, Shoulder / Q000379:methods*; D005260:Female; D062785:Hemiarthroplasty; D006801:Humans; D007595:Joint Prosthesis; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000601:surgery*; D016059:Range of Motion, Articular / Q000502:physiology; D012042:Registries; D012086:Reoperation; D012785:Shoulder Joint / Q000601:surgery*; D016896:Treatment Outcome