Stress fractures of the heads of the metatarsals. A new cause of metatarsal pain.

We report 16 cases of epiphyseal metatarsal stress fractures in 11 patients. Four patients had osteoporosis and two of these four were under fluoride therapy. Three of the fractures occurred upon resumption of weight-bearing. The fractures were distributed over the five rays; seven fractures were located to the second metatarsal. Manifestations were acute focal metatarsal pain, diffuse edema of the forefoot and inflammatory metatarsophalangeal arthropathy. Delayed, transient visualization of a linear area of epiphyseal sclerosis occurred in 14 cases. Radionuclide bone scans consistently showed early accumulation of the tracer in the metatarsal head. The focus of increased activity extended to the shaft in three cases. The main differential diagnoses are second ray syndrome, metatarsophalangeal arthritis, focal radial reflex sympathetic dystrophy of the foot and osteonecrosis of the metatarsal heads. The clinical and roentgenographic outcome was consistently favorable after one month without weight-bearing. These fractures can simulate, complicate, induce (two cases), reflex sympathetic dystrophy of the foot or occur concomitantly with (two cases).