A Comprehensive Study of the Anatomical Variations of the Posterolateral Tubercle of Talus

Abstract

The aim of our study was to determine the prevalence and the anatomical variations of the posterolateral tubercle of talus in relation to sex on CT imaging. A total of 1478 ankle CT scans was retrospectively reviewed for the different anatomical variants of the posterolateral tubercle of talus, the type and size of os trigonum. Normal sized lateral tubercle was found in 46.1 %, an enlarged posterolateral tubercle (Stieda's process) in 26.1 %, os trigonum in 20.5 % and almost absent tubercle in 7.3 %. A statistically higher prevalence of Stieda's process was found in males while os trigonum was higher in females (p<0.05). Among feet with os trigonum, 25.7 % were non-articulating and identified as a separate bone located posterior to the posterolateral tubercle of talus and 74.3 % of os trigonum were identified as fused to the posterolateral tubercle by synchondrosis or syndesmosis. Additionally, 17.5 % of os trigonum were associated with intact lateral tubercle, 53.5 % were considered as part of the lateral tubercle and 29.0 % were without a lateral tubercle. According to its size, 22.8 % of os trigonum were smaller than 0.5 cm, 55.4 % were between 0.5 and 1cm, and 21.8 % were larger than 1 cm. No significant differences were found between the different types/sizes of os trigonum according to gender (p>0.05). The posterolateral tubercle of talus and its accessory ossicle, the os trigonum, could vary morphologically. The data of this study could be helpful in understanding the clinical problems that could be associated with some of these variants.

Accessory Ossicles in the Region of the Foot and Ankle: An Epidemiologic Survey in a Jordanian Population

“…The incidence rates of os trigonum, accessory navicular and os peroneum in our subjects were higher than the rates of 2.3%, 11.7% and 4.7% reported by Coskun et al [9], but lower than the 23.5%, 28.2% and 31.8% reported by Cilli et al [8]. Additionally, in our previous studies, the frequency of occurrence for os trigonum and accessory navicular was considerably higher in comparison with the current study (26.1% and 22.9%, respectively) [19,20]. One of the reasons could be that CT scans were used for os trigonum detection, which have higher sensitivity for detecting accessory ossicles compared to conventional radiographs.…”

The Stieda process of the talus: the anatomical knowledge and clinical significance of an overlooked protrusion

“…Although there are different classifications in the literature, SP and OT are entirely different from each other, and their differentiation is necessary to treat caused disorders properly. Furthermore, a higher prevalence of SP was found in males, while OT was higher in females (Kalbouneh et al 2021). In the study of Zwier et al, the frequency of SP was found in about one-third of the patients without OT, with an incidence of 35.7% in the Netherlands (Zwiers et al 2018).…”

“…Little knowledge about the incidence of SP is available in the literature (Kalbouneh et al 2021). It might result from the SP that has not part of a standard definition or classification system (Kalbouneh et al 2021).…”

“…Little knowledge about the incidence of SP is available in the literature (Kalbouneh et al 2021). It might result from the SP that has not part of a standard definition or classification system (Kalbouneh et al 2021). Studies on SP (mostly case studies) have examined its symptoms, clinical significance, and treatment plan (Table 1).…”

“…(Sarrafian and Kelikian 2011). The following types were classified in the literature: type 1 (absent tubercle), type 2 (typical tubercle), type 3 (SP), and type 4 (OT) (Kalbouneh et al 2021). Fu et al stated that type 1 was a single bone that was not connected to the talus, type 2 was connected to the posterior process of the talus by hyaline cartilage, and type 3 was the SP (Fu et al 2019).…”