CASE 6158 Published on 12.09.2007

Blount Disease

Section

Musculoskeletal system

Case Type

Clinical Cases

Authors

Prepared by: 1.Dr Osama Ahmed Elzamazmi,FRCR in diagnostic radiology. Dubai Hospital.PO Box 7272 Dubai.UAE Osam_zam@yahoo.com 2.Dr jassem ibrahim. Facharzt in diagnostic radiology. Dubai Hospital.PO Box 7272 Dubai.UAE Email: jassem_ibrahim@hotmail.com

Patient

9 years, male

Clinical History
9-year-old male obese child presented with bowing deformity of the left knee and length discrepancy, together with pain and tenderness related to abnormal medial prominence at proximal tibia.
Imaging Findings
9-year-old male obese child presented with bowing deformity of the left knee and length discrepancy, together with pain and tenderness related to abnormal medial prominence at proximal tibia. Plain X-ray & CT of the knee show marked tibial varus deformity with increased metaphyseal diaphyseal angle above 20 degrees in addition to marked irregularity, destruction, fissuring, sclerosis, collapse and deformity of the proximal metaphyseal sub epiphyseal region with multiple air lucencies and marginal peaking.
Discussion
Blount Disease: The local disturbance of growth of the medial and dorsal segments of the proximal tibial metaphysis and adjacent epiphysis in this condition is also called tibia vara. When the deformity is noted between 1 and 6 years of age, it is termed infantile Blount disease and is six to eight times as frequent as the more severe adolescent type appearing later. It may be unilateral or bilateral. The characteristic radiographic feature is an abrupt lateral bending of the medial cortical wall of the proximal metaphysis of the tibia with a spur and above it a more or less vertically oriented continuation of the superior border of the metaphysis. The medial portion of the epiphyseal ossification center is smaller than the lateral portion, and its superior margins, the future medial portion of the tibial plateau, slopes downward and medially. Blount disease was considered an osteochondrosis (i.e., a result of ischemic necrosis), but the metaphyseal defect is due to replacement of bone by cartilage extending downward from the epiphysis. The condition is differentiated from physiological bowing and bowing of rickets and of metaphyseal chondrodysplasia by the sharp cortical angle, but serial examinations may be necessary to establish the increasing local deformity that is part of the disease. Occasionally, similar deformities can be observed in the opposing femur at the knee.
Differential Diagnosis List
Adolescent Blount Disease
Final Diagnosis
Adolescent Blount Disease
Case information
URL: https://www.eurorad.org/case/6158
DOI: 10.1594/EURORAD/CASE.6158
ISSN: 1563-4086

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