Aseptic glenoid baseplate loosening after reverse total shoulder arthroplasty: A systematic review and meta-analysis

Background:Aseptic glenoid baseplate loosening can lead to the failure of reverse total shoulder arthroplasty (RTSA). Estimates of the prevalence of aseptic glenoid baseplate loosening after RTSA are required to guide clinical decisions, but published results are variable and lack precision. The goal of this meta-analysis was to determine a precise estimate of the prevalence of aseptic glenoid baseplate loosening after RTSA and to explore variation in the prevalence according to different variables, such as the type of procedure (primary or revision), preoperative diagnosis, the center of rotation of the glenoid component (medialized or lateralized), study size, the definition of aseptic glenoid baseplate loosening, and the duration of follow-up.Methods:The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. We searched the MEDLINE and Embase databases for English-language articles describing the outcomes after RTSA with a minimum 12-month follow-up in which radiographic findings of aseptic glenoid baseplate loosening were reported. Random-effects meta-analysis was performed, and meta-regression was used to explore the influence of variables on heterogeneity. Subgroup analyses and sensitivity analyses were performed.Results:One hundred and three studies (covering 6,583 RTSAs) performed from 1991 to 2015 met our inclusion criteria. The pooled prevalence of radiographic aseptic glenoid baseplate loosening for all RTSAs was 1.16% (95% confidence interval [CI], 0.80% to 1.69%). The prevalence of aseptic glenoid baseplate loosening was lower among primary RTSAs (0.90%; 95% CI, 0.54% to 1.49%) than among revision RTSAs (3.64%; 95% CI, 1.91% to 6.84%). The pooled prevalence of aseptic glenoid baseplate loosening by diagnosis was 2.69% for osteoarthritis with bone loss, 1.71% for cuff tear arthropathy, 1.20% for rheumatoid arthritis, 1.08% for sequelae of fracture, 0.94% for irreparable massive cuff tear, and 0.25% for acute proximal humeral fracture. The prevalence of aseptic glenoid baseplate loosening was not significantly different for prostheses with a medialized center of rotation (1.15%) versus a lateralized center of rotation (1.84%).Conclusions:To our knowledge, the present study represents the first meta-analysis investigating only aseptic glenoid baseplate loosening after RTSA. Multiple variables were found to be associated with the prevalence of aseptic glenoid baseplate loosening. The rates reported here are lower than those reported previously because of the inclusion of more recent evidence and more studies that evaluated aseptic glenoid baseplate loosening.