Metadiaphysis
The Metaphysis is the end of a long bone where the growth in the length of the bone occurs in growing children, or occurred in adults, and can be proximal or distal. The Diaphysis is the shaft portion of the long bone, and it does not contribute to growth in length of the bone in growing children or adults. The "Metadiaphysis" is the junction of/between the Metaphysis and the Diaphysis, including growing children and adults. Technically, a Metadiaphyseal fracture is neither a Metaphyseal nor a Diaphyseal Fracture, but at occurs at their junction. In the proximal radius, the only site that could be considered a "Metadiphyseal Fracture" is the Radial Neck. It would be far better to not use this term for this fracture, and just call it a Radial Neck Fracture, particularly to avoid confusion in coding.
Respectfully submitted, Alan Pechacek, M.D.
icd10orthocoder.com