Purpose: Annual rates of knee arthroplasty are increasing in all developed countries, imposing a significant economic and organizational burden; it is crucial to forecast the future need for knee arthroplasty, to assist stakeholders in planning strategies and investments, especially in a country like Italy, with the largest proportion of elderly citizens in Europe. Few epidemiological studies have been performed worldwide to estimate the demand for future knee replacement, and a variety of methods have been proposed.Methods: We investigated the epidemiology of knee arthroplasty performed in Italy in the last 15 years and projected incidence rates up to the year 2050, utilizing, comparing, and adapting the available methodologies.Results: From 2001 to 2016, 812,639 primary TKA were performed in Italy on patients over 40. The total number of surgeries increased by 262% with an average annual growth rate of 6.6%.Conclusions: Adopting the best fitting projection method, an increase of 45% in incidence rate is expected for 2050. [ABSTRACT FROM AUTHOR]