Trends of shoulder arthroplasty and rotator cuff repair in Japan: national database analysis

Abstract

Background

Reverse total shoulder arthroplasty was introduced to Japan in 2014, principally to treat cuff tear arthropathy and irreparable massive rotator cuff tears. Its indications have expanded significantly worldwide since then. This study aimed to analyze the annual trends in shoulder arthroplasties and rotator cuff repairs (RCRs) from 2014 to 2022 and to examine differences by sex and age group using a publicly available national database.

Methods

We conducted a retrospective analysis using data from the National Database of Health Insurance Claims and Specific Health Checkups provided by the Ministry of Health, Labour, and Welfare in Japan. The surgical categories analyzed included shoulder arthroplasty and RCR between 2014 and 2022. The annual number of surgeries was reported according to sex and age group. Age-specific incidence was calculated per 100,000 people using age group population data. Descriptive statistics and the independent t-test were used for comparisons by sex and age, and linear regression analysis was applied to assess trends.

Results

Shoulder arthroplasties increased dramatically from 1,246 in 2014 to 5,439 in 2022. From 2014 to 2022, the number of RCRs did not decrease; in fact, they continued to increase steadily from 17,553 to 21,183, except for a dip in 2020. Shoulder arthroplasties were nearly twice as common in females, whereas RCRs were more frequent in males. Shoulder arthroplasties peaked in the 75-79 age group, with an average age of 78 years, whereas RCRs were most frequent in the 70-74 age group, averaging 67 years.

Discussion and Conclusion

Despite the substantial increase in shoulder arthroplasties, the number of RCRs has also slightly increased. These findings demonstrate that reverse total shoulder arthroplasty did not simply replace RCRs but complement conventional RCR in the treatment spectrum of shoulder disorders. The findings indicated that females had a higher prevalence of shoulder arthroplasty procedures, whereas males were more likely to undergo RCR. In addition, the patients who underwent shoulder arthroplasty tended to be older than those who underwent RCR. These observations may be attributed to sex-specific differences in the progression of shoulder conditions and the accessibility of various treatment approaches or possibly a difference in indications for surgery in females and males. This study demonstrated substantial increases in shoulder arthroplasties in Japan over the past decade, with notable differences in age and sex distributions compared with conventional RCR.