Overuse ballet injury of the base of the second metatarsal. A diagnostic problem.

Performing classical ballet may cause major stress to the feet of the dancer. A variety of foot injuries have been described, with one such injury being an overuse syndrome involving the base of the second metatarsal and adjacent Lisfranc's joint. The diagnosis for this syndrome usually requires differentiating synovitis of Lisfranc's joint from a stress reaction of the base of the second metatarsal. Prompt diagnosis is important since the treatment for these two conditions differs significantly and, in the case of bone stress reaction, delay can cause progression of the lesion. We report good clinical results in a group of eight ballerinas for whom we obtained early diagnosis and treatment of their injuries. This is in contrast to poor results reported in the literature if the diagnosis and management of these types of injuries are delayed. We developed a simple diagnostic protocol to enable diagnosis at presentation. When a bone stress reaction had progressed to a fracture line, a characteristic appearance was found on magnetic resonance imaging, suggesting a specific mechanism of injury. A possible mechanism for this injury is discussed.