Incidence of referred carpal tunnel syndrome and carpal tunnel release surgery in the general population: Increase over time and regional variations.

Purpose: To investigate the change in incidence of referred carpal tunnel syndrome (CTS) and carpal tunnel release (CTR) surgery over time and regional variations. Methods: From the nationwide patient registry, we identified all adult individuals who had received first-time CTS diagnosis (International Classification of Diseases, 10th Revision code G560) at secondary or tertiary level and first-time CTR surgery during the period of 9 years. Results: From 2001 through 2009, the incidence (per 100,000 person-years) of CTS diagnosed at secondary or tertiary level increased from 216 to 243 in women and from 95 to 119 in men and of CTR from 117 to 168 in women and from 52 to 78 in men. The mean annual increase in first-time CTR (95% confidence interval) was 5.1% (4.7-5.4) in women and 6.2% (5.6-6.7) in men. The age-standardized 3-year (2007-2009) incidence varied significantly across Sweden's 21 counties; compared to the county with the lowest incidence of CTR, the incidence rates in the other counties were higher by 6-152% (mean 60%) in women and by 20-182% (mean 85%) in men. The proportion of CTS-diagnosed individuals treated with surgery varied across counties from 53% to 81% in women and from 51% to 77% in men. Conclusion: The incidence of referred CTS and of CTR surgery increased over time in both sexes, with large regional variations found in the incidence rates and in the proportion of individuals treated with surgery.