Trends in isolated meniscus repair and meniscectomy in Japan, 2011–2016

Meniscus surgery is the most commonly performed orthopedic surgery, and despite recent emphasis on saving the meniscus, the current status of meniscus surgeries is little known in many countries, including Japan. The National Database of Health Insurance Claims and Specific Health Checkups of Japan and the Statistics of Medical Care Activities in Public Health Insurance track meniscus surgeries through health insurance claims. The National Database provides the numbers for 2014 and 2015, and the Statistics of Medical Care Activities provides the numbers from June 2011 to June 2016. Our aim was to analyze isolated meniscus surgery numbers and meniscus repair ratios by age group based on the National Database and evaluate trends of meniscus repair ratios for the latest six years from the Statistics of Medical Care Activities. Meniscus surgeries by age group were counted from the National Database for 2014–2015, and meniscus repair ratios (meniscus repairs/meniscus surgeries) were calculated. The numbers were also counted from the Statistics of Medical Care Activities in 2011–2016. For statistical analysis of annual trends of meniscus repair ratios, the Cochran–Armitage trend test was used. Meniscus surgeries with concomitant knee ligament surgeries were excluded. According to the National Database, isolated meniscus surgeries totaled 34,966 in 2015, with peak ages of patients in their late teens and 60s. The meniscus repair ratio was 19% in 2014 and 24% in 2015. According to the Statistics of Medical Care Activities, the meniscus repair ratio was 9% in 2011 and significantly increased to 25% in 2016 (p = 0.0008). The ratio also increased significantly in each age group between the early 20s and late 70s. Approximately 35,000 meniscus surgeries are performed in Japan annually, with peak ages in the late teens and 60s. The number of meniscus repairs has increased over the past six years.