The incidence of fractures of the clavicle.

The age- and gender-specific incidences were calculated in 2035 cases of fracture of the clavicle. The fractures were classified in three groups according to the Allman system. Each group was further divided into undisplaced and displaced fracture subgroups, with an extra subgroup of comminuted midclavicular fractures in Group I. Seventy-six percent of the fractures were classified as Allman Group I. The median age in this group was 13 years. There were significant differences in age- and gender-specific incidence between the undisplaced, displaced, and comminuted fracture subgroups. Twenty-one percent were classified as Allman Group II. The median age of the patients was 47 years, and there was no difference in age between the undisplaced and displaced fracture subgroups. Three percent were classified as Allman Group III, and the median age of the patients in this group was 59 years. All three groups were characterized by a significant preponderance of men, and there was a significant increase in the incidence of clavicular fracture, both overall and sports-related, between 1952 and 1987.