Reverse Shoulder Arthroplasty in the United States: A Comparison of National Volume, Patient Demographics, Complications, and Surgical Indications.

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.