Posterior tibial tendon impingement due to os subtibiale: a case report and up-to-date review.

Os subtibiale is a rare accessory ossicle located at the tip of the medial malleolus. Although this small ossicle usually has no clinical significance, in some cases it may be a source of ankle pain. Symptomatic os subtibiale is an extremely rare diagnosis, and few cases have been reported to date. The case presented is of a 35-year-old female patient with symptomatic os subtibiale, with a discussion of the diagnosis, clinical findings, and treatment options.