Projected numbers of knee and hip arthroplasties up to the year 2030 in Japan.

Background The aging population is a risk factor for an increase in osteoarthritis, leading to a potential increase in the number of arthroplasties worldwide. This study aimed to calculate the projected numbers of knee and hip arthroplasties in Japan until 2030 using national health insurance claim data. Methods Data on the numbers of knee and hip arthroplasties performed in Japan between 2014 and 2018 were obtained from the National Database of Health Insurance Claims and Specific Health Checkups of Open Data Japan. Demographic data were obtained from the National Institute of Population and Social Security Research. Collected data were categorized into three age subgroups (40-64, 65-74, and ≥75 years) for each sex. Projections were based on the Poisson regression model. Results The number of knee arthroplasties in Japan in 2030 was projected to be 4052 for men aged 40-64 years, 6942 for men aged 65-74 years, 14,986 for men aged ≥75 years, 7092 for women aged 40-64 years, 22,957 for women aged 65-74 years, and 58,340 for women aged ≥75 years. The number of hip arthroplasties in Japan in 2030 was predicted to be 8936 for men aged 40-64 years, 9005 for men aged 65-74 years, 5972 for men aged ≥75 years, 27,327 for women aged 40-64 years, 36,416 for women aged 65-74 years, and 37,011 for women aged ≥75 years. Conclusion The numbers of knee and hip arthroplasties are expected to continue to increase over the next 10 years in Japan in most age groups. These findings are useful for future healthcare resource planning to meet the demand for knee and hip arthroplasties.