Frequency of Os trigonum and Stieda process, determination of its relation with posterior ankle pain and tendinopathy by ankle MRI

Abstract

ABSTRACT
 Aim: To investigate the frequency of Os trigonum and Stieda process and the relationship of Os trigonum with other pathologies detected by magnetic resonance imaging (MRI) in patients with posterior ankle pain.
 Methods: This was a retrospective study conducted by re-examining MRI images obtained between January 2017 and May 2023. The study included 482 patients (496 ankles) who underwent ankle MRI for diagnostic purposes due to posterior or posterolateral ankle pain. MRI images were re-examined for the following parameters: fractures, contusion, tendinosis, ligament injury, arthritis, effusion, presence of Stieda process, posterior ankle bursa impingement, Os trigonum, retrocalcaneal bursitis, ganglion cyst, widespread osteophytes, accessory navicular bone, presence and grade of osteochondritis dissecans, and presence and type of Achilles tendon pathology. 
 Results: The mean age of the participants was 41.96 ± 15.89 (7–83 years), and 51.04% (n = 246) were male. Os trigonum was detected in 17 patients (3.43 %), and none of the cases were bilateral. The likelihood of Os trigonum was significantly higher in males (p = 0.016, OR: 4.725, 95% CI: 1.341 - 16.655). Stieda process was detected in 186 patients (37.5 %). The accessory navicular bone was detected in 8 (1.61%). The percentage of patients with pathological metatarsal fractures was significantly higher in patients with Os trigonum (p = 0.034). The frequency of Stieda process was significantly lower in patients with Os trigonum (p = 0.013, OR: 0.099, 95% CI: 0.013 - 0.755). There were significantly fewer cases of talotibial effusion in the Os trigonum group (p = 0.030).
 Conclusion: While Os trigonum appears to be significantly more frequent among males, it is less frequent in the presence of the Stieda process and talotibial effusion.