The epidemiology of odontoid fractures: a study from the Swedish fracture register

The objective of this study is to characterize the occurrence of odontoid fractures within a Swedish population.

Prospective data of adults diagnosed with an odontoid fracture between 2015 and 2021 were retrieved from the Swedish Fracture Register (SFR). Epidemiologic data including age, sex, injury mechanism, injury type, fracture type (Anderson and D'Alonzo classification), neurological status and treatment type were requested from the SFR. Data pertinent to osteoporosis was retrieved from the Swedish National Patient Register.

A total of 1,154 odontoid fractures were identified, of which 30 were type I fractures, 583 type II fractures, and 541 type III fractures. The mean (Standard Deviation [SD]) age was 77.2 (13.8) years. The prevalence of osteoporosis and neurological deficits did not differ between the fracture types. The majority of patients were treated non-surgically (81%). Male sex and patient age 18-30 years were commonly associated with a high-injury mechanism, especially motor vehicle accidents. In the type II fracture group, significantly more patients had fallen from standing height or less than in the type III group (66% vs. 58%, p = 0.01) while in contrast, motor vehicle accidents were more common in the type III fracture group (12% vs. type II: 8%, p = 0.04).

Based on the SFR, the typical odontoid fracture patient is older and suffers a type II fracture. Most injuries were caused by low-energy trauma although in younger patients and males, they were associated with motor vehicle accidents. Across the patient population, odontoid fractures were usually treated non-surgically.