Villonodular Synovitis of the Subtalar Joint: A Case Report

INTRODUCTION: Villonodular synovitis (SVN) is a rare benign pseudotumoral proliferation of the synovial joint, of unknown etiology. In general, it reaches the big joints, especially the knee. Localization at the subtalar level is extremely rare, with only a few cases published in the literature. CASE REPORT: We report the case of an SVN of the subtalar in a 60-year-old patient without particular histories, who consulted for a swelling of the external border of the right foot evolving for 2 years. Biology, as well as the standard radiographs, was without anomalies. The diagnosis was evoked on magnetic resonance imaging (MRI) and confirmed by surgical biopsy and excision. The operative follow-up was simple with no recurrence after 3 years. CONCLUSION: SVN of the subtalar is rare. Surgical treatment is based mainly on synovectomy, and the prognosis depends mainly on the osteocartilaginous lesion and the quality of excision.