Paediatric Radiology

Case 4 :

A 6 year old male child with tenderness and weakness of lower extremities. Radiographs of the knee have been taken.
What is the diagnosis ?

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Imaging Findings:

Radiographs show almost all features possible seen in scurvy. The classical ground glass osteoporosis, cortical thinning, halo ossification center, lateral spurs, and subperiosteal hematomas.

A deficiency of ascorbic acid causes abnormal function of the osteoblast and defective osteogenesis resulting in osteoporosis. Clinical symptoms and signs of infantile scurvy, in order of frequency are irritability, tenderness and weakness of lower extremities, a scorbutic rosary of the legs, bleeding of the gums (usually where teeth have erupted), and fever. Normal plasma level of ascorbic acid is 0.6 mg per 100 ml, so a lab value of at least this level excludes scurvy.

Radiological Findings:
Dense metaphyseal line
This is due to an intensification of the zone of preparatory calcification, resulting from matrix formation failing, is has been referred to as the white line of Frankel, but is non-specific, as it is also seen in healing rickets, and lead or phosphorus poisoning.

Ground Glass Osteoporosis
This appears at the end of the shaft with blurring or disappearance of trabecular markings.

Halo Ossification Centre
Also called the Wimberger's ring, it is the same effect that produces the white line of Frankel, affecting the epiphyseal ossification center.

Cortical Thinning
Corner Sign
Seen due to subepiphyseal infraction, or separation of the epiphysis from the metaphysis.

Lateral Spurs
These metaphyseal spurs project at right angles to the axis of the shaft, they may be seen due to mushrooming of epiphysis on the metaphysis, or may represent earliest calcification of periosteum elevated by a subperiosteal hemorrhage.

Subperiosteal hematomas
These occur at the end of long bones, seen after about 2 weeks of onset of clinical symptoms; it is not the periosteal hemorrhage that calcifies, but the elevated periosteum, secondary to resumption of bone formation.

Metaphyseal Fractures
Subperiosteal comminuted fractures at the end of long bones, extending only partially through the width of the bone.

Atrophic scurvy line
A radiolucent zone on the shaft side of Frankel's white line, it has been referred to as the Trummerfeld Zone.

Dr. Vinod Naneria
Orthopedic Surgeon
Choithram Hospital and Research Centre