Epidemiology of long bone non-unions in Spain

Epidemiological and ecological studies on long bone non-unions (NU) are scarce, based on different populations and methodologies. The aim of this study was to produce a descriptive analysis of the femur, tibia, and humerus non-union epidemiology in Spain. Methods Data were obtained from the Minimum Basic Data (Conjunto Mínimo Básico de Datos, CMBD) Hospital Discharge Database of the Spanish Ministry of Health, according to the ICD9-CM coding for diagnoses and procedures, and from the National Institute of Statistics for population, generating secondary databases with the reported cases that included the code 733.82 in a disaggregated manner, by age (categorized in 5 intervals), gender, Spanish region, and calendar year (1997-2015). Percentage of non-unions related to fractures in the previous year, annual prevalence (expressed per 100,000 person-years) and period prevalence (expressed per 100,000 person-period) were calculated by age, gender, and Spanish regions. The Odds ratio (OR) was estimated with a confidence of 95% using a logistic regression model per anatomical site. Results A mean of 235,446 fractures in all locations were annually reported in Spain from 1997 to 2015. Regarding non-union of long bones (femur, tibia and humerus), a total of 37,053 cases were found, representing a yearly mean of 1,950 cases. The proportion of long bone fractures that evolved into a non-union was 4% (1.4% femur, 1.5% tibia, and 1% humerus). The mean annual prevalence rate of NU in Spain was estimated in 4.5 (3.7-4.9) cases per 100,000 persons-year. The overall NU prevalence in Spain was estimated in 86 cases per 100,000 persons. By the type of bone, the period prevalence (per 100,000 persons-period) of the femur NU was 31, of the tibia 33, and of the humerus 22. Conclusions This description of the epidemiology of long bone non-unions in Spain confirms that the overall non-union rate has been stable from 2000 to 2015, higher in the tibia and in the femur compared to the humerus. NU occurred more frequently in aged females than in males in the femur and the humerus, while the tibia non-unions were more frequent in males and younger age.