Imaging of painful conditions of the hallucal sesamoid complex and plantar capsular structures of the first metatarsophalangeal joint.

Numerous injuries and pathologic conditions can involve the hallucal sesamoidal complex and plantar capsular structures of the first metatarsophalangeal joint. Although clinical history and presentation are important in developing a reasonable differential diagnosis, there is often considerable overlap in the clinical presentation and physical findings between various pathologic entities. Imaging plays an important role in narrowing the differential diagnosis and in directing appropriate therapy. This article reviews the normal anatomy of the hallucal sesamoidal complex and the plantar capsular structures of the first metatarsophalangeal joint. Typical clinical presentations are discussed for various pathologic entities that involve this area of the hallux, followed by a summary of the various imaging findings that occur when using conventional radiography, nuclear medicine bone scan, CT and MR imaging. Finally, general treatment guidelines are discussed for each entity.