Bone marrow edema in the foot—MRI findings after conservative therapy

Abstract

Bone marrow edema (BME) is a rare cause of pain in the foot. We reviewed 23 patients with unilateral idiopathic bone marrow edema located in the foot. The patients' mean age was 59.1 years (32–73). Bone marrow edema was located 12 times in the talus, four times in the cuneiform bones, four times in the metatarsal bones, two times in the calcaneus, and once in the navicular bone. Edema secondary to an activated osteoarthritis, to mechanic stress, to a chronic regional pain syndrome or to trauma were excluded. The size of BME was categorized large in nine cases (50–100% of the bone involved), in nine cases medium (25–50%) and in five cases small (<25%). Conservative therapy consisted of infusions with the vasoactive substance iloprost and limited weight-bearing for a period of three weeks. After 3 months, in 15 patients BME showed total regression on MRI scan. In three there was subtotal regression and in three no change in the size of the BME ( p <0.0001). No correlation between the primary size of BME and outcome was seen ( p =0.453). No progression to AVN occurred in our patients. In two patients BME appeared to migrate to neighbouring bones and in one patient to a femoral head. Conclusions . Bone marrow edema syndrome is rarely seen in the foot. Progress to avascular necrosis is unlikely. Conservative therapy can be recommended.