Lifetime risk of primary shoulder arthroplasty over a decade: a population-level analysis

Abstract

Purpose: Lifetime risk estimates can serve as a marker for disease burden in a population and enable health funders and the health workforce to plan for healthcare demand. While the lifetime risk of hip and knee arthroplasty have previously been estimated at national levels, this approach has not yet been applied to shoulder arthroplasty. This study aimed to quantify the lifetime risk of primary shoulder arthroplasty in Australia, and examine changes in lifetime risk over a ten-year period. Methods: De-identified individual-level data on all primary partial shoulder arthroplasty (PSA) and total shoulder arthroplasty (TSA) procedures performed in Australia from 1 January 2008 to 31 December 2017 were obtained from the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR). The AOANJRR has a near-complete capture rate (>98.8%) of all hip, knee and shoulder arthroplasties performed in Australia, and registry data are validated against state-level health department data using a sequential multi-level matching process. The full collection of AOANJRR national shoulder arthroplasty data commenced in 2008. Population data and life tables (incorporating life expectancy and all-cause mortality) were obtained from the Australian Bureau of Statistics. The lifetime risk of primary PSA and primary TSA was calculated for each year from 2008-2017 using AOANJRR data, population data and life tables data, according to a standardised formula. Separate calculations were undertaken for males and females. Results: From 2008 to 2017, a total of 38,868 primary shoulder arthroplasties were performed. Of these, 5,979 (15%) were PSA procedures and the majority (N=32,889, 85%) were TSA procedures. Glenohumeral osteoarthritis was the most common reason for both PSA (53% in 2017) and TSA (57% in 2017). The lifetime risk of PSA decreased significantly for both sexes over time. For males, lifetime risk decreased from 0.25% (95% CI 0.22% to 0.28%) in 2008 to 0.11% (95% CI 0.09% to 0.13%) in 2017. For females, lifetime risk decreased from 0.55% (95% CI 0.51% to 0.60%) to 0.11% (95% CI 0.09% to 0.13%). In contrast, there was a significant increase in the lifetime risk of TSA. For males, this tripled from 0.54% (95% CI 0.49% to 0.58%) in 2008 to 1.68% (95% CI 1.60% to 1.76%) in 2017. For females, lifetime risk more than doubled from 0.99% (95% CI 0.92% to 1.05%) to 2.77% (95% CI 2.67% to 2.88%). Conclusions: Compared to declining PSA trends, there was substantial growth in TSA use over a decade. To put these findings in context, the lifetime risk of TSA in Australia increased to 1 in 60 for males and 1 in 40 for females by the end of 2017. The steep increase in lifetime risk of TSA over time probably relates to addressing previously unmet need for surgery, given the increasing availability of skilled surgeons trained to perform the procedure and advances in prosthesis design and materials. Greater awareness among patients and health professionals of successful outcomes following TSA may have also contributed to the observed growth. These data improve our understanding of the rising national burden of primary TSA, and can assist in planning to meet future surgical demand. The methods used for this study can also be re-applied in future years for ongoing population-level surveillance and to facilitate a planned international comparison.