Metaphyseal corner fracture

Metaphyseal corner fracture is, also termed classical metaphyseal lesion (CML), is a fracture observed in young children (<2 years). It is considered pathognomic for non-accidental injury (NAI)¹.

Prevalence

This injury is not only the fracture most specific for NAI, it is also common amongst abused children, occurring in 39-59%

Pathophysiology

The biomechanics of metaphyseal fracture is the cumulation of multiple microfractures across the metaphysis with an orientation perpendicular to the long axis of the bone. To-and-fro manipulation (shaking) is the force applied, for example holding the child around the trunk while shaking, with the limbs moving back and forth with a resultant whiplash, or shear force. The microfractures occur in immature mineralised bone.

This injury occurs almost exclusively in children under 2 years of age because 1) they are small enough to thebe shaken; 2) they cannot protect their limbs.

Radiographic features

Radiography

lucentLucent area within the subphyseal metaphysis perpendicular to the long axis of the bone. The fracture extends across the metaphysis (completely or partially)

Nuclear medicine

Like other fractures there is increased uptake of technetium-99m methylene diphosphonate. However, intense uptake of technetium-99m methylene diphosphonate at the metaphyses is normal in young children,; abnormally increased uptake may be difficult to identify. Therefore scintigraphy is considered complementary only (as far as metaphyseal corner fractures are concerned).