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Meta-Analysis
. 2025 Jun;100(3):287-297.
doi: 10.1007/s12565-024-00811-4. Epub 2024 Nov 26.

Prevalence and clinical aspects of os trigonum: a meta-analysis

Maciej Preinl  1   2 , Aleksander Osiowski  1   2 , Kacper Stolarz  1   2 , Maksymilian Osiowski  1   2 , Dominik Taterra  3   4
Affiliations
Meta-Analysis

Prevalence and clinical aspects of os trigonum: a meta-analysis

Maciej Preinl et al. Anat Sci Int. 2025 Jun.

Abstract

Os trigonum (OT) is one of the most common accessory ossicles in the foot and ankle region. It is believed that OT was first described by Rosenmuller in 1804, but von Bardeleben is the one who coined the nomenclature for this anatomical variation in 1883. The literature indicates that OT is extremely variable in prevalence, with reported rates ranging from 1.7% to 32.5%. In clinical practice, OT is a considerable factor that may predispose patients to posterior ankle impingement syndrome (PAIS). The aim of this study was to provide comprehensive data on the prevalence and anatomical characteristics of OT. We conducted a comprehensive search of the main electronic databases to find the relevant research. Information concerning geographical origin, prevalence, gender distribution, imaging modality, and morphometry of OT was extracted. The PRISMA guidelines were strictly followed throughout the study. The reliability of the included studies was assessed using the AQUA tool. A total of 41 studies (n = 36,612 feet) were included in this meta-analysis. This meta-analysis showed that OT was present in 9.0% (95% CI: 7.4-10.8) of the feet, and was present bilaterally in 32.7% (95% CI: 23.3-43.7) of cases. Regarding the types of imaging modality used in the evaluation of OT by the included studies, prevalence assessed by X-rays was 8.2% (95% CI: 6.8-9.9), MRI was 24.2% (95% CI: 14.6-37.3), CT was 21.0% (95% CI: 12.8-32.5), and cadaveric dissection was 5.0% (95% CI: 3.4-7.4). OT was most commonly found in East Asia (11.0%, 95% CI: 7.1-16.8). Two studies provided enough data to calculate the odds ratio linking PAIS with OT. The analysis showed that patients with PAIS are almost 16 times more likely to have OT compared to those without PAIS (OR = 15.98, 95% CI = 0.255-1002.8). OT is a very common accessory ossicle and is present in nearly one in 10 feet. The highest prevalence is noted in the East Asian population. MRI and CT show the highest prevalence of OT. It is important to keep in mind the possible presence of OT when a patient is diagnosed with PAIS.

Keywords: Accessory ossicle; Anatomy; Foot and ankle anatomical variation; Os trigonum; Posterior ankle impingement syndrome.

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Conflict of interest statement

Declarations. Competing interests: The authors have no relevant financial or non-financial interests to disclose. Ethics approval: Not applicable for this type of study (systematic review with meta-analysis).

Figures

Fig. 1
Fig. 1
Illustrative diagram of os trigonum in relation to talus
Fig. 2
Fig. 2
Medial view of posterior ankle with the presence of os trigonum
Fig. 3
Fig. 3
Flowchart of the meta-analysis
Fig. 4
Fig. 4
Forest plot presenting general prevalence of os trigonum
See this image and copyright information in PMC

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