Forecasting the future burden of primary total shoulder replacement in Australia

Objective: To forecast the number of primary total shoulder replacements (TSR) in Australia to the year 2035, and associated costs. Methods: De-identified TSR data for 2009–2019 were obtained from the Australian Orthopaedic Association National Joint Replacement Registry. Population data, including population projections to 2035, were obtained from the Australian Bureau of Statistics. Three forecasting scenarios were used: constant TSR rates from 2019 onwards (Scenario 1, conservative); continued growth in TSR rates using negative binomial regression (Scenario 2, exponential); and continued growth using negative binomial regression with monotone B-splines (Scenario 3, moderate). Healthcare costs were estimated using TSR projections and average procedure costs, inflated to 2035 Australian dollars. Results: The use of TSR increased by 242% in Australia from 2009 to 2019 (from 1983 to 6789 procedures for people ≥40 years). Under Scenario 1, the incidence of TSR is conservatively projected to rise to 9676 procedures by 2035 (43% increase from 2019), at a cost of $AUD 312.6 million to the health system. Under Scenario 2, TSR incidence would increase to 45,295 procedures by 2035 (567% increase), costing $AUD 1.46 billion. Under Scenario 3, 28,257 TSR procedures are forecast in 2035 (316% increase) at a cost of $913 million. Conclusions: Recent growth in TSR likely relates to prosthesis improvements, greater surgeon proficiency, and expanded clinical indications. Under moderate and exponential scenarios that consider rising TSR rates and population projections, Australia would face three- to five-fold growth in procedures by 2035. This would have profound implications for the healthcare budget, clinical workforce, and infrastructure.