title: Reverse Shoulder Arthroplasty in the United States: A Comparison of National Volume, Patient Demographics, Complications, and Surgical Indications.
abstract: BACKGROUND
  Shoulder arthroplasty is increasing in the United States. Reverse shoulder arthroplasty (RSA) has emerged as an alternative treatment for end-stage glenohumeral pathology. Until recently, administrative coding practices have not differentiated RSA from traditional total shoulder arthroplasty (TSA), and thus national procedural volume has been unknown. The purpose of this study was to define the utilization, patient characteristics, indications and complications for RSA, and contrast these to TSA and hemiarthroplasty (HA).
  
  
  METHODS
  The 2011 Nationwide Inpatient Sample (HCUP-NIS) dataset was queried using ICD-9-CM codes to identify patients undergoing RSA, TSA, or HA. We used weighted estimates of national procedure volume, per-capita utilization, patient comorbidities, and inpatient complications denned by the Agency for Healthcare Research and Quality (AHRQ) and identified them using standard methods described by Elixhauser. ANOVA statistical analysis was used and significance was denned as p value <0.05.
  
  
  RESULTS
  In 2011, 66,485 patients underwent shoulder arthroplasty; there were 21,692 cases of RSA, 29,359 of TSA, and 15,434 of HA. Utilization of RSA and TSA increased between 2002-2011, and decreased for HA. RSA patients were older (72.7 years vs 67.4 TSA vs 66.8 HA) and more commonly female. Comorbidity burden was highest in patients undergoing HA. Inpatient complications were highest after RSA (p < 0.001). When compared to TSA, RSA was more commonly used in the setting of rotator cuff disease, and posttraumatic sequelae (p<0.001).
  
  
  CONCLUSIONS
  Our findings represent the first national estimates of RSA within the United Sates. RSA is a significant contributor to increasing shoulder arthroplasty utilization nationally representing one-third of arthroplasty cases. Conditions traditionally managed with HA in older populations appear to now be more commonly managed with RSA. RSA is performed on older patients with expanded indications.
authors.affiliation: Department of Orthopaedic Surgery and Rehabilitation, University of Iowa Hospitals and Clinics , Iowa City, IA , USA.
authors.forename: Robert W
authors.initials: RW
authors.lastname: Westermann
authors.affiliation: Department of Orthopaedic Surgery and Rehabilitation, University of Iowa Hospitals and Clinics , Iowa City, IA , USA.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Pugely
authors.affiliation: Department of Orthopaedic Surgery and Rehabilitation, University of Iowa Hospitals and Clinics , Iowa City, IA , USA.
authors.forename: Christopher T
authors.initials: CT
authors.lastname: Martin
authors.affiliation: Department of Orthopaedic Surgery and Rehabilitation, University of Iowa Hospitals and Clinics , Iowa City, IA , USA.
authors.forename: Yubo
authors.initials: Y
authors.lastname: Gao
authors.affiliation: Department of Orthopaedic Surgery and Rehabilitation, University of Iowa Hospitals and Clinics , Iowa City, IA , USA.
authors.forename: Brian R
authors.initials: BR
authors.lastname: Wolf
authors.affiliation: Department of Orthopaedic Surgery and Rehabilitation, University of Iowa Hospitals and Clinics , Iowa City, IA , USA.
authors.forename: Carolyn M
authors.initials: CM
authors.lastname: Hettrich
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D019643:Arthroplasty, Replacement / Q000379:methods* / Q000706:statistics & numerical data; D016208:Databases, Factual; D003710:Demography; D005260:Female; D062785:Hemiarthroplasty / Q000379:methods* / Q000706:statistics & numerical data; D006801:Humans; D015994:Incidence; D007595:Joint Prosthesis; D008297:Male; D008875:Middle Aged; D010003:Osteoarthritis / Q000453:epidemiology / Q000503:physiopathology / Q000601:surgery*; D010147:Pain Measurement; D018579:Patient Selection; D011183:Postoperative Complications / Q000453:epidemiology / Q000503:physiopathology; D011475:Prosthesis Failure; D016059:Range of Motion, Articular / Q000502:physiology; D020127:Recovery of Function; D012086:Reoperation; D012189:Retrospective Studies; D018570:Risk Assessment; D012785:Shoulder Joint / Q000503:physiopathology / Q000601:surgery*; D016896:Treatment Outcome; D014481:United States