Regional Variation in Wrist Ligament Surgery Incidence: A 25-year Nationwide Register Study.

Background: This register study investigates regional variation in the incidence of wrist ligament surgery across 5 catchment areas in Finland. The primary objectives are to evaluate geographic differences in surgical incidence and to compare rates between public and private hospitals. Methods: Data were obtained from the Finnish National Hospital Discharge Register, which includes all procedures performed in both public and private hospitals in Finland. Procedures were identified using the International Classification of Diseases and the Nordic Classification of Surgical Procedures. Annual incidence rates were calculated per 100,000 adult person-years, and comparisons were made across regions and between public and private hospitals. Results: The incidence of wrist ligament surgery varied considerably across catchment areas. During the study period, the mean annual incidence differed by more than 2-fold between some regions. Substantial differences were also observed between public and private hospitals. Although incidence increased in both sectors over the years, it was more pronounced in private hospitals. During the study period, the average annual increase in private hospitals was approximately twice that observed in public hospitals across most regions. In the area with the highest incidence of private procedures, private hospitals performed approximately 3 times as many wrist ligament procedures as public hospitals during the peak years. Conclusions: The observed regional variation in the incidence of wrist ligament surgery is unlikely to reflect differences in actual ligament injuries. Instead, these disparities are more likely driven by factors such as local treatment cultures, surgeon preferences, and sector-specific practices.