Female, 21 years old. Pain, tenderness. Fibular Great Toe Sesamoid Fx vs BiPartite. Low signal intensity replaces the normal fatty marrow of the lateral hallux sesamoid on T1 and T2-weighted images, which also appears fragmented or at least bipartite. There is minimal if any edema associated with this sesamoid on fluid sensitive sequences. These findings are suggestive of osteonecrosis. The medial sesamoid appears normal, as does the adjacent first metatarsal head. The proximal and distal phalanges of the great toe appear normal. The flexor hallucis longus tendon appears normal. The remaining bones of the forefoot appear normal.
Low signal intensity with probable fragmentation of the lateral hallux sesamoid bone likely representing osteonecrosis. If further evaluation of the degree of fragmentation is desired, CT can be considered.