Bipartite hallucal sesamoid bones: relationship with hallux valgus and metatarsal index.

Abstract

The objective was to relate the incidence of the partition of the hallucal sesamoid bones to the size of the first metatarsal and the hallux valgus deformity. In a sample of 474 radiographs, the frequency of appearance of bipartite sesamoids was studied. The length and relative protrusion of the first metatarsal, and the hallux abductus angle, were measured and compared between the feet with and without sesamoid partition. The results showed that 14.6% of the feet studied had at least one partite sesamoid, that the sesamoid most frequently divided was the medial, and that unilateral partition was the most common. No difference was found in the incidence of partite sesamoids between men and women, or between left and right feet. Protrusion and length of the first metatarsal are greater in feet with partite sesamoids than in feet without this condition. A significantly higher incidence of bipartite medial sesamoid was obtained in feet with hallux valgus compared with normal feet.