Epidemiology of cruciate ligament surgery in Japan: A repeated cross-sectional study from 2014 to 2021

Understanding the incidence and trends of cruciate ligament (CL) surgeries in Japan is crucial for providing effective healthcare services. This study aimed to use open data available from the National Database of Health Insurance Claims and Specific Health Checkups of Japan (NDB) to analyze changes in CL surgeries over time and the characteristics of the Japanese population by sex and age. We retrospectively identified CL surgeries of the knee joint registered from April 2014 to March 2022 using the NDB open data. Data on sex, age, and practice were extracted to determine the number of cases per 100,000 population. Trends in the annual incidence of CL surgeries were evaluated using Poisson regression analysis. A total of 142,931 CL surgeries were performed from 2014 to 2021, with arthroscopic ligament reconstruction accounting for 98% of cases. The number of surgeries significantly increased from 16,975 in 2014 to 19,735 in 2019 (P<0.001). CL surgeries were most common in the 15-19 and 20-29 years age groups, with variations between males and females. The incidence of CL surgery in Japan has increased, with characteristics varying by sex and age, including middle-aged and older patients. Further investigation of general patterns in CL surgery in Japan would be valuable.