BACKGROUND: Avascular necrosis of the humeral head (AVN) is characterized by osteonecrosis secondary to disrupted blood flow to the glenohumeral joint. Following collapse of the humeral head, arthroplasty, namely total shoulder arthroplasty (TSA) or humeral head arthroplasty (hemiarthroplasty) is recommended standard of care. The literature is limited to underpowered and small sample sizes in comparing arthroplasty modalities. Therefore, the aims of this study were (1) to compare the 10-year survivorship of TSA and hemiarthroplasty in the treatment of AVN of the humeral head and (2) to identify differences in their revision etiologies.
METHODS: Patients who underwent primary TSA and hemiarthroplasty for AVN were identified using the PearlDiver database. TSA patients were matched by age, gender, and Charlson Comorbidity Index (CCI) to the hemiarthroplasty cohort in a 4:1 ratio since TSA patients were generally older, sicker, and more often female. The 10-year cumulative incidence rate of all-cause revision was determined using Kaplan-Meier survival analysis. Multivariable analysis was conducted using Cox Proportional Hazard modeling. Chi-squared analysis was conducted to compare the indications for revisions between matched cohorts including periprosthetic joint infection (PJI), dislocation, mechanical loosening, broken implants, periprosthetic fracture, and stiffness.
RESULTS: In total, 4,825 patients undergoing TSA and 1,969 patients undergoing hemiarthroplasty for AVN were included in this study. The unmatched 10-year cumulative incidence of revision for patients who underwent TSA and hemiarthroplasty was 7.0% and 7.7%, respectively. The matched 10-year cumulative incidence of revision for patients who underwent TSA and hemiarthroplasty was 6.7% and 8.0%, respectively. When comparing the unmatched cohorts, TSA patients were at significantly higher risk of 10-year all-cause revision (HR: 1.39; P = 0.017) when compared to hemiarthroplasty patients. After matching, there was no significant difference in risk of 10-year all-cause revision (HR: 1.29; P = 0.148) and no difference in the observed etiologies for revision (P > 0.05 for all).
CONCLUSIONS: After controlling for confounders, only 6.7% of TSA and 8.0% hemiarthroplasties for humeral head AVN were revised within 10-years of index surgery. The demonstrated high and comparable long-term survivorship for both modalities supports the utilization of either for the AVN induced humeral head collapse.

BACKGROUND: To assess the extent of between-hospital variation in revision following primary shoulder arthroplasty (SA), both overall and for specific revision indications to guide quality improvement initiatives, and to assess whether revision rates are suitable as quality indicators to reliably rank hospital performance.
METHODS: All primary SAs performed between 2014 and 2018 were included from the Dutch Arthroplasty Register to examine 1-year revision and all primary SAs performed between 2014 and 2016 for 1- and 3-year revisions. For each hospital, the observed number (O) of revisions was compared with that expected (E) based on case-mix and depicted in funnel plots with 95% control limits to identify outlier hospitals. The rankability (ie, the reliability of ranking hospitals) was calculated as the percentage of total hospital variation due to true between-hospital differences rather than chance and categorized as low (<50%), moderate (50%-75%), and high (>75%).
RESULTS: A total of 13,104 primary SAs (87 hospitals) in 2014-2018 were included, of which 7213 were performed between 2014 and 2016. Considerable between-hospital variation was found in 1-year revision in 2014-2016 (median 1.6%, interquartile range 0.0%-3.1%), identifying 3 outlier hospitals having overall significantly more revisions than expected (O/E range 1.9-2.3) and for specific indications (cuff pathology and infection). Results for 2014-2018 were similar. For 3-year revision, 3 outlier hospitals were identified (O/E range 1.7-3.3). Rankabilities for all outcomes were low.
CONCLUSIONS: Considerable between-hospital variation was observed for 1- and 3-year revision rates following primary SA, where outlier hospitals could be identified based on large differences in revision for specific indications to direct quality improvement initiatives. However, rankabilities were low, meaning that much of the other (smaller) variation in performance could not be detected, rendering revisions unsuitable to rank hospital performances following primary SA.