Introduction Overview bone infarcts are often thought to be in the same spectrum of disease as osteonecrosis occurs within the metaphysis or diaphysis of long bone Epidemiology & Incidence similar risk factors as those seen in osteonecrosis trauma, sickle cell disease, connective tissue disorders, Gaucher's disease, steroid use Mechanism interruption of blood supply by intrinsic or extrinsic factors Presentation Symptoms usually asymptomatic often found when imaging the extremities for other reasons Imaging Radiographs medullary lesion of sheet-like central lucency surrounded by sclerosis with a serpiginous border "smoke up the chimney" MRI key feature is that central signal remains of normal marrow T1 weighted images peripheral low signal due to grannulation tissue and to lesser extent sclerosis periphery may enhance post gadolinium T2 weighted images acute infarct may show ill-defined non-specific area of high signal intense inner ring of granulation tissue and a hypointense outer ring of sclerosis Bone Scan cold in early phases hot in late resorptive and revascularisation phase Treatment Nonoperative observation indications usually asymptomatic and do not require treatment
QUESTIONS 1 of 1 1 Previous Next PASS Peak is our new Personalized Adaptive Learning System. The beta version will be available to VC members free for a limited time. Click here for more information on PASS Peak. (OBQ08.167) A 45-year-old female twists her knee suddenly while playing tennis. She denies any history of knee pain in the past. Radiographs are shown in Figure A. What is the diagnosis? Review Topic QID:553 FIGURES: A 1 Bone infarct 81% (1136/1397) 2 Osteonecrosis 2% (26/1397) 3 Metastatic carcinoma 1% (14/1397) 4 Osteosarcoma 1% (7/1397) 5 Enchondroma 15% (204/1397) Select Answer to see Preferred Response PREFERRED RESPONSE 1 Idiopathic bone infarcts often occur in the metaphysis of long bones such as the femur and tibia. They are often asymptomatic and found on imaging studies for other reasons. The infarcted area undergoes progressive, but incomplete resorptive replacement. The bone infarct becomes surrounded by a thick and calcified fibro-osseous wall in a healing attempt. This accounts for the blotchy medullary and linear peripheral shadows seen in radiographs of old bone infarcts resembling “smoke up the chimney”. Bone scans are cold in the early stages and hot as revascularisation occurs. The etiology is thought to be related to intrinsic/extrinsic vascular compromise such as atherosclerosis, arteritis, and thrombosis. Biopsy (usually unnecessary) shows mineralization of necrotic marrow elements. Bone infarcts usually are asymptomatic, and no treatment is required. If a patient presents with pain, another etiology should be sought. Rarely, malignancy, such as a malignant fibrous histiocytoma, can occur at the site of a bone infarct Authors: Jan Szatkowski MD, Michael Hughes MD, Please rate question. Average 3.0 of 14 Ratings Question COMMENTS (8) Please login to add comment.