title: Effect of glenoid cementation on total shoulder arthroplasty for degenerative arthritis of the shoulder: a review of the New Zealand National Joint Registry.
abstract: BACKGROUND
  Despite the lack of literature showing improved results compared with cemented designs, uncemented glenoid components are still commonly used in total shoulder arthroplasty (TSA). Most studies comparing cemented with uncemented glenoids involve small numbers or include patients with inflammatory arthritis.
  
  
  METHODS
  New Zealand National Joint Registry data was used to compare the outcomes of uncemented and cemented glenoids in TSA performed for degenerative arthritis. Measured variables were the revision rate and the Oxford Shoulder Score (OSS).
  
  
  RESULTS
  Data were retrieved on 1596 patients, with a mean follow-up 3.5 years (range 2-10.7 years), 1065 of whom had a cemented glenoid. There were no significant differences in any preoperative factors between the 2 groups. The revision rate for uncemented glenoids was 4.4 times higher than for cemented glenoids (1.92 vs. 0.44 revisions per 100 component-years, P < .001). Age <55 years was an independent risk factor for revision (P < .001). The most common reason for revision was rotator cuff wear (35.5%) in the uncemented glenoids and loosening (36.3%) in the cemented glenoids. The difference in the mean OSS between the 2 groups was less than 1 point at 6 months (P = .109) and at 5 years (P = .377).
  
  
  CONCLUSIONS
  Uncemented glenoids had a markedly higher revision rate. Patients aged <55 years have the highest revision rate regardless of glenoid fixation method. The higher revision rate in the uncemented glenoid group persisted when the effect of young age was corrected for. There was no clinically or statistically significant difference in the OSS results for clinical outcome between the two groups.
  
  
  METHODS
  Level III, retrospective cohort, treatment study.
authors.affiliation: Department of Orthopaedic Surgery, North Shore Hospital, Auckland, New Zealand. Electronic address: harry_sc@hotmail.com.
authors.forename: Harry D S
authors.initials: HD
authors.lastname: Clitherow
authors.affiliation: Department of Medicine, The University of Otago, Christchurch, New Zealand.
authors.forename: Christopher M A
authors.initials: CM
authors.lastname: Frampton
authors.affiliation: Department of Orthopaedic Surgery, North Shore Hospital, Auckland, New Zealand.
authors.forename: Timothy M
authors.initials: TM
authors.lastname: Astley
mesh_terms: D000368:Aged; D019643:Arthroplasty, Replacement / Q000379:methods*; D002484:Cementation; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009520:New Zealand; D010003:Osteoarthritis / Q000601:surgery*; D012042:Registries; D012086:Reoperation; D012189:Retrospective Studies; D012540:Scapula / Q000601:surgery*; D012785:Shoulder Joint / Q000601:surgery*; D016896:Treatment Outcome
keywords: Total shoulder arthroplasty; cemented; clinical outcome; glenoid; joint registry; revision rate; uncemented