Nonunions and Their Operative Treatment-A DRG-Based Epidemiological Analysis for the Years 2007-2019 in Germany.

BACKGROUND
Nonunions, which arise as a complication of fractures, are an important medical and socio-economic problem. The goal of this study was to analyze nonunions in Germany with respect to the patients' age and sex, the anatomical site of the lesions, and their operative treatment.


METHODS
The study was performed on the basis of DRG (diagnosis-related group) data acquired for billing purposes and collected by the German Federal Statistical Office. The administrative frequencies of nonunions and fractures treated in the inpatient setting, broken down by sex and age group, were calculated from the documentation of ICD codes. An investigation was also made of surgical treatments for nonunion, as they were categorized by the German procedure classification (Operationen- und Prozedurenschlüssel, OPS).


RESULTS
The administrative frequency of nonunion was 14.84 per 100 000 persons per year, with a 2% decline in case numbers over the period 2007-2019. Nonunions develop in 2% of fractures. Nonunions affect men more often than women (58% vs. 42%). In men, their incidence as a function of age is highest under age 30; in women, it rises steadily with increasing age. The most common type of surgical treatment is a combination of resection, bone transplantation, and osteosynthesis.


CONCLUSION
This is the first detailed nationwide study of diagnoses of nonunions in Germany and their surgical treatment. Despite a slow decline in their incidence, nonunions remain an important problem in the inpatient setting. The risk profile for nonunions is sex-, age-, and sitespecific.