Fracture complicating the bone marrow edema syndrome

Bone marrow edema syndrome (BMES), also known as transient regional osteoporosis, is a rare and poorly understood disease process. We present a case of an elderly patient with the BMES who had a relapsing and remitting course complicated by a hip fracture which presented the unique and a previously unreported opportunity to examine the bony architecture pathologically. The patient responded well to calcitonin and bisphosphonate therapy after surgical repair of his fracture. This case highlights an underappreciated potential complication of BMES. Though not previously reported in the literature, BMES may be associated with active osteoporotic changes, with an infrequent risk of fracture that may be amenable to potential therapeutic interventions. Pathologically, BMES may represent a spectrum of disease consisting of an osteoclast-rich phase (transient regional osteoporosis phase) predisposing to fracture in addition to the more indolent osteoclast-poor phase with bone marrow edema more commonly associated with the disease. We hypothesize that it is the osteoclastic-rich phase which may benefit from early introduction of weight bearing activities, calcitonin, bisphosphonates, or parathyroid hormone. For example, bisphosphonates reduce bone resorption directly. Indirectly, bisphosphonates may also increase osteoblast differentiation and number and thus improve bone quality, an added benefit in the treatment of bone involved in the BMES, whether in the osteoclast-rich or osteoclast-poor phase. Further study should evaluate this osteoclastic-rich phase, which may be a transient pathologic phenomenon and which has not been described previously. Transient regional osteoporosis, therefore, may represent one point in the spectrum of the BMES. Hence, we would argue that BMES is a more accurate name for the full spectrum of this disease entity.