Pathological femoral fractures due to osteomalacia associated with adefovir dipivoxil treatment for hepatitis B: a case report

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/1600344696739249Hypophosphatemic osteomalacia caused by proximal renal tubule dysfunction induces Fanconi’s syndrome, which leads to impaired reabsorption of amino acids, glucose, urate, and phosphate [1]. The chronic loss of phosphate and impaired synthesis of 1,25-dihydroxyvitamin D3 may lead to failure of bone mineralization. Recently, osteomalacia was reported in cases in which hepatitis B virus and human immunodeficiency virus (HIV) infections were treated using high-dose adefovir dipivoxil [2-6]. We report a case of a patient who underwent total hip arthroplasty for pathological femoral neck fracture associated with osteomalacia induced by low-dose adefovir dipivoxil treatment.A 62-year-old man started experiencing pain in the right knee and left shoulder pain in January 2010. He visited a clinic and was administered salazosulfapyridine and methylprednisolone therapy for rheumatoid arthritis. However, the pain gradually increased, and he started experiencing pain in his hip joints as well. Therefore, he was admitted our hospital for further examination in February 2011. He had a 7-year history of chronic hepatitis caused by hepatitis B virus infection, and had received lamivudine therapy for 2？years. Because the virus developed resistance to lamivudine, he received adefovir dipivoxil for 5？years before the development of the femoral neck fracture. After adefovir dipivoxil treatment, his liver function was restored. Radiography showed femoral neck fractures (right, Garden III fracture; left, Garden IV fracture) and a distal right tibial fracture (Figure？1a) [7]. Magnetic resonance imaging (MRI) of both hip joints showed fractures across the right and left femoral neck and bone edema, which had low intensity on T1-weighted images and high intensity on T2-weighted images (Figure？1b). 99mTc-hydroxymethylene diphosphonate (HMDP) whole-body bone scintigraphy showed