The Stieda process (SP) and os trigonum (OT) are primary risk factors for posterior ankle impingement syndrome. The aim of this study was to elucidate the prevalence of the elongated lateral tubercle of the posterior talar process (SP) and OT in Turkish subjects using lateral ankle radiographs. In this study, 1088 ankle radiographs in the lateral view were evaluated retrospectively using a picture archiving and communication system at two large medical centers. Subjects with a history of mild-to-moderate trauma were selected from the emergency departments of both hospitals from January to June 2019. Data on the presence of SP and OT, the side of the foot that was evaluated, sex, and age were recorded. The prevalence of SP and OT was 16.7 % and 9.3 %, respectively, in the Turkish population. The prevalence of SP was significantly higher in men (20.3 %) than in women (12.7 %) (p = 0.001). The prevalence of OT was also significantly higher in men (13.7 %) than in women (4.3 %) (p = 0.000). The SP and OT were found in 17 % and 9.9 % of the right feet, respectively, and 16.4 % and 8.6 % of the left feet, respectively, with no statistical difference. Approximately one-fourth of the Turkish population had SP or OT, which made them susceptible to posterior ankle impingement syndrome. The prevalence of SP was higher than that of OT, and both were more common in men than in women.
KEY WORDS: Stieda process; Os trigonum; Lateral radiography; Ankle; Turkish population.