Gruberi bursitis in rheumatic patients with foot and ankle pain: a retrospective sonographic study

Plamen Todorov Todorov ^* Lili Mekenyan Boryana Levterova Anastas Batalov

• Plovdiv Medical University, Plovdiv, Bulgaria

Introduction: Foot and ankle pain is a frequent problem in rheumatic patients. One underrecognized cause for this complaint is the Gruberi, or subtalar, bursitis. The Gruberi bursa is a structure that originates from the sinus tarsi and extends up over the dorsal talar surface. It reduces the friction of the extensor digitorum longus tendon over the convex contour of the head of the talus. On ultrasound, the Gruberi bursitis is characterized by a well-defined fluid collection in the dorsolateral foot -between the talus and the tendon of extensor digitorum longus. The aim of our study was to determine the frequency of occurrence of the Gruberi bursitis in patients with various rheumatic diseases, presenting with foot and ankle pain in our institution, as well as to describe in detail its sonographic features. Material and methods: A descriptive, observational, retrospective study was conducted on patients over 18 years old who visited a tertiary university hospital between July 1, 2022, and December 31, 2023. Details regarding the patients' medical history, age, gender, and primary rheumatic disease were obtained from their medical records. Descriptive statistics were utilized to present the data. Results: Out of the 608 subjects examined due to foot and ankle pain at our institution during the study period, 78 cases of Gruberi bursitis in 63 patients were identified. The average age of the participants was 61.7 years (range: 25-85 years), and 71% (n=45) were female. The sonographic features of the Gruberi bursitis included a monocular, anechoic fluid collection with a typical location between the extensor digitorum longus tendon and the dorsolateral surface of the head of the talus. The mean of the largest dimension of the fluid collections in the oblique plane (from sinus tarsi and across the dorsal talus) was 16 mm (range: 8-29 mm). Conclusion: The Gruberi bursitis is easy to be identified by ultrasound due to its characteristic location and appearance. In total, we identified this condition in 9% of our rheumatic patients with foot and ankle pain.