Os Trigonum syndrome – A case report

Abstract

INTRODUCTION: Os trigonum syndrome is one of the rare causes of posterior foot pain. Os trigonum, which is placed at the posterior of talus, appears as an ossification center between ages 7-13 years, and generally joins with talus in one year-time, is an accessory bone. In 7% of the population, it does not join with talus, and it is defined as os trigonum syndrome, when this structure becomes symptomatic. We aim to present our case, which is a rare disease and is generally missed out. CASE: 65-year old female patient with the complaint of left foot pain for the last 2 months, was admitted to our clinics. The severity of the pain on the posterior of her foot was increasing especially during a walk. The patient reported no redness, swelling or morning stiffness and there was no history of trauma. The physical examination revealed that active and passive motion ranges of ankle and toe were complete, whereas plantar flexion was painful. Pain VAS was 8 cm. There was sensitivity at the posterior of talus during deep palpation. ESR and CRP levels were all within normal limits. While there was os trigonum on left ankle lateral radiography, spur formation was detected on posterior talus in MRI examination, and the patient was diagnosed as os trigonum. Treatment included non-steroidal anti-inflammatory drugs, TENS, cold pack as well as a physiotherapy program with ROM strengthening exercises for ankle and toe. After the treatment, pain VAS due to forced plantar flexion of the toe decreased to 2 cm, and then the patient was followed up. CONCLUSION(S): Os trigonum syndrome is a pathology leading to posterior foot pain. As in our case, os trigonum syndrome should also be remembered in the differential diagnosis of patients complaining of posterior foot pain, apart from other frequently encountered causes.