Spontaneous fusion of the midfoot following reflex sympathetic dystrophy. A case report and review of the literature.

Reflex sympathetic dystrophy syndrome (RSDS) is a well-defined entity, caused by many clinical conditions, leading to pain, stiffness, and vasomotor changes in the affected region. In this case, a 49-year-old man presented with a history of right foot pain secondary to a fall. Plain radiographs did not reveal any fractures or bony fusions. Upon follow-up, a history consistent with that found in RSDS was given. Radiographs at 7 and 11 weeks revealed increasing osteopenia, lytic lesions, and absent joint spaces in the first through third metatarsocuneiform articulations suggesting ankylosis. Other possible causes of ankylosis, including infection, inflammatory and metabolic conditions, were excluded.