CASE BASED REVIEW Transient osteoporosis of the hip, complete resolution after treatment with alendronate as observed by MRI description of eight cases and review of the literature Yasser Emad & Yasser Ragab & Nashwa El-Shaarawy & Johannes J. Rasker Received: 13 July 2012 / Accepted: 9 August 2012 # Clinical Rheumatology 2012 Abstract Transient osteoporosis of the hip (TOH), also referred to as transient bone marrow edema syndrome, is most common in middle-aged men and often after trivial trauma or sport-related injuries. Diagnosis is usually made by eliminating other possible causes of hip pain. Magnetic resonance imaging (MRI) plays an important role in diag- nosis and demonstrates a typical pattern of bone marrow edema (BME) in the form of diffuse low signal on T1- weighted images and high signal on T2 fat-suppressed or short T1 inversion recovery images. No consensus exists about the management of TOH, as it may progress to avas- cular necrosis. We describe eight cases of TOH treated with alendronate resulting in improvement of pain and function and complete resolution of BME on MRI. The literature is reviewed regarding TOH and the relationship with bone marrow edema syndrome, avascular necrosis of the hip, and regional migratory osteoporosis. To our knowledge, this is the first report describing the improvement of this condi- tion after of alendronate with documented radiological im- provement on follow-up MRI. Keywords Alendronate . Bone marrow edema syndrome . Magnetic resonance imaging (MRI) . Transient osteoporosis of the hip Introduction Bone marrow edema syndrome (BMES) refers to transient clinical conditions with unknown pathogenic mechanisms, including many entities such as transient osteoporosis of the hip (TOH), regional migratory osteoporosis (RMO), and reflex sympathetic dystrophy (RSD). BMES is primarily characterized by bone marrow edema (BME) pattern. The disorder mainly affects the hip, the knee, and the ankle of middle-aged males. Many hypotheses have been proposed to explain the pathogenesis of the disease. Unfortunately, the etiology of BMES remains obscure. The hallmark that separates BMES from other conditions presented with BME pattern is its self-limiting nature. BME is a general term describing an area of low-signal intensity on T1-weighted and high-signal intensity on T2- weighted and short T1 inversion recovery (STIR) magnetic resonance (MR) images [1]. It is important to note that BME affecting the hip joint is neither a specific magnetic reso- nance imaging (MRI) finding nor a specific diagnosis. BME of the hip joint cannot only be encountered in TOH but also Y. Emad (*) Rheumatology and Rehabilitation Department, Faculty of Medicine, Cairo University, Cairo, Egypt e-mail: yasseremad68@yahoo.com Y. Emad Rheumatology and Rehabilitation Department, Dr. Erfan and Bagedo General Hospital, Jeddah, Saudi Arabia Y. Ragab Radiology Department, Faculty of Medicine, Cairo University, Cairo, Egypt Y. Ragab Radiology Department, Dr. Erfan and Bagedo General Hospital, Jeddah, Saudi Arabia N. El-Shaarawy Rheumatology and Rehabilitation Department, Faculty of Medicine, Suez Canal University, Ismailia, Egypt J. J. Rasker Rheumatology Department, University of Twente, Enschede, The Netherlands Clin Rheumatol DOI 10.1007/s10067-012-2060-y