Authors of section


Arnold Besselaar, Daniel Green, Andrew Howard

Executive Editor

James Hunter

General Editor

Fergal Monsell

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33-M/7   Metaphyseal, avulsion


Ligament avulsions are classified as M-fractures by convention, even when they occur in the epiphysis.

Medial, lateral, or bilateral avulsion fractures of the distal femur are classified as 33-M/7m, 33-M/7l, and 33-M/7, respectively.

These fractures are rare.

Metaphyseal avulsion of the distal femur

Injury types

Twisting injuries may result in disruption of the medial or lateral collateral (MCL, LCL), anterior or posterior cruciate ligaments (ACL, PCL).

The MCL and ACL are most commonly injured.

Small avulsion fractures may represent markers of significant injuries, including knee dislocation and require MRI to determine the extent of the injury.

Ligaments of the knee

Pellegrini-Stieda lesion

Injury of the medial collateral ligament at its femoral attachment can result in local pain and heterotopic ossification. This combination is referred to as the Pellegrini-Stieda lesion.

Pellegrini-Stieda lesion
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