Posttraumatic sesamoid arthritis of the metacarpophalangeal joint of the thumb.

The articular interface between the radial sesamoid and the radial condyle of the metacarpal head, which is the radial subsesamoid joint, is the most frequently involved area of abnormality in the metacarpophalangeal joint complex. More than 85% of all adult cadavers demonstrate degenerative arthritis of the radial subsesamoid joint. Confusing this condition with degenerative arthritis of the metacarpophalangeal joint may lead to unnecessary joint fusions. The predisposition of the radial subsesamoid to degenerative arthritis is related to the asymmetry of the palmar condyles of the metacarpal. The ulnar sesamoid has a flatter and broader condyle compared with the radial sesamoid, which rides on a high, narrow ridge. Thirty-six patients with symptomatic sesamoiditis have been treated by sesamoidectomy since 1978. Twenty-one of these patients were available for follow-up examination between 1 and 5 years after surgery, and 19 had relief of proximal thumb pain after sesamoidectomy.