The Rare Lesser Metatarsal Bipartite Sesamoid – A Case Report and Literature Review

Abstract

INTRODUCTION AND OBJECTIVES: There are several various accessory ossicles and sesamoid bones that can be seen throughout the foot and ankle, with reported incidence of 21.2% and 9.6%, respectively. Accessory ossicles and sesamoid bones usually remain asymptomatic until an inciting event (trauma, overuse) occurs and can then cause pain or degenerative changes. They can also be found in routine imaging. One of these confusing findings are lesser metatarsal sesamoids, which are a rare occurrence. Here radiographically we demonstrate the first such case of a fifth metatarsal bipartite sesamoid. METHODS: A 31-year old female presented to the senior authors office for evaluation of the right foot after a motor vehicle accident (MVA). She was told she sustained a foot fracture at an outside emergency department. Her case was reviewed for presentation. RESULTS: Physical exam did not elicit any pain to the forefoot as all symptoms were in the patients ankle. The initial radiograph was reviewed which revealed a bipartite sesamoid of the fifth metatarsal. No pedal fractures to the foot or ankle were appreciatd. MRI was ordered and confirmed this diagnosis with no active pathology to the forefoot. CONCLUSIONS: number one at 7.6% and foot and ankle at 51.4%, respectively. One study found that initial emergency room diagnosis and final foot and ankle outpatient clinic diagnosis did not match in 21.4% of patients evaluated. Lesser metatarsal sesamoids are more common in the 2nd and 5th metatarsal and overall range between 0.2–15%. However, no literature to the authors knowledge exists demonstrating a bipartite lesser sesamoid, and more specifically to 5th metatarsal.