Type 2 Odontoid Fractures: Atlantodental Arthrosis as a Novel Risk Factor for Failure of Conservative Management

Retrospective case-control study.

The purpose of this study is to assess how the presence and grade of atlantodental arthrosis impact outcomes of nonoperatively managed type 2 odontoid fractures.

The nonoperative management of geriatric type 2 odontoid fractures requires consideration of all potential variables that may influence outcomes. The presence of underlying atlantodental arthrosis can create a more rigid lever arm adjacent to the fracture site inducing greater biomechanical strain on an already tenuous healing environment.

Eighty-one patients with traumatic type 2 odontoid fractures managed nonoperatively were included, with an average follow-up of 180 days after injury. Radiographic evaluation was performed to identify the presence and severity of atlantodental arthrosis on computed tomography (CT) imaging at the time of injury. Electronic medical records were reviewed to report patient demographics, fracture characteristics, and treatment outcomes. The relationship between atlantodental arthrosis and failure of conservative management was primarily assessed.

Patients who failed conservative treatment were more likely to have an atlantodental arthrosis grade >2 ( P <0.001) and increased posterior displacement on index imaging ( P =0.008). Following multivariable regression, grade 3 (OR: 4.4, 95% CI: 1.6-11.9, P =0.004) and grade 4 arthrosis (OR: 13.9, 95% CI: 1.5-127.9, P =0.02) were independently associated with an increased risk for failing conservative management.

The present findings identify the presence of atlantodental arthrosis as a risk factor for treatment failure in conservatively managed geriatric type 2 odontoid fractures. Future prospective studies are necessary to further elucidate the prognostic value of arthrosis severity in determining optimal treatment strategies.