Does alar ligament injury predict conservative treatment failure of atlantoaxial rotatory subluxation in adults: Case report and review of the literature.

INTRODUCTION The alar ligament is an important structure in restraining the rotational movement at the atlantoaxial joint. While bony fractures generally heal, rupture of ligaments may heal poorly in adults and often requires surgical stabilization. Atlantoaxial rotatory subluxation (AARS) is a rare injury in adults, and the prognostic importance of the presence of alar ligament injury with regard to the success of nonoperative management is unknown. CASE PRESENTATION A 28-year-old woman presented after a traumatic Type I AARS without evidence of osseous injury, but MRI demonstrated evidence of unilateral alar ligament disruption. Initial conservative management with closed reduction and maintenance in a rigid cervical collar proved unsuccessful, with worsening pain and failure to maintain reduction. She subsequently underwent open reduction and surgical fixation of C1-C2, resulting in resolution of her pain and maintenance of alignment. DISCUSSION Alar ligament rupture may be a negative prognostic indicator in the success of nonoperative management of type I atlantoaxial rotatory subluxation. Additional study is warranted to better assess whether the status of the alar ligament should be considered an important factor in the management algorithm of type I AARS.