Etiology of ankle osteoarthritis.

UNLABELLED: The purpose of this study was to evaluate the distribution rate of etiologies leading to ankle arthritis and to quantify and compare the important clinical and radiologic variables among these etiologic groups. We evaluated data from 390 patients (406 ankles) who consulted our center because of painful end-stage ankle osteoarthritis (OA) by using medical history, physical examination, and radiography. Posttraumatic ankle OA was seen in 78% of the cases (n = 318), secondary arthritis in 13% (n = 52), and primary OA in 9% (n = 36). The average American Orthopaedic Foot and Ankle Society (AOFAS) hindfoot score was 38 points (range, 0-74 points), range of motion was 22 degrees (range, 0 degrees-65 degrees), and visual analog scale for pain was 6.8 (range, 2-10). Patients with posttraumatic end-stage ankle OA were younger than patients with primary OA. The average tibiotalar alignment was 88 degrees (range, 51 degrees-116 degrees) and did not differ between the etiologic groups. Our study showed trauma is the main cause of ankle OA and primary OA is rare. In the majority of patients with ankle OA the average tibiotalar alignment is varus regardless of the underlying etiology. LEVEL OF EVIDENCE: Level IV, prognostic study.