Boxer fracture

Q: What is this fracture known as? show answer

A: Boxer fracture.

Q: What is the mechanism of injury and what are the two most commonly involved objects? show answer

A: A poorly thrown punch, usually against a human face or a wall.

Q: Who is usually afflicted by this injury? show answer

A: The vast majority (~95%) are young men.

Q: What are important features to assess for and comment upon? show answer

A: Morphology of the fracture (transverse, spiral, comminuted, oblique etc...); intra-articular extension (and size of any step-off); degree of impaction / shortening; degree of angulation; degree of rotation.

Q: How is rotation assessed? How much is acceptable? Why? show answer

A: This is best assessed on AP view; rotation manifests as apparent angulation. Rotation is also evident clinically. No significant abnormal rotation is acceptable as this results in overlap of the fingers during clenching.

Q: What is the normal (anatomical) degree of palmar angulation of the fifth metacarpal head? show answer

A: Approximately 15 degrees.

Q: How would you measure the degree of angulation and what is acceptable? show answer

A: Asses the apex of angulation dorsally by drawing lines parallel to the long axis of the bone, ideally on lateral projection. The closer to the neck the greater the degree of angulation is acceptable: 20 degrees for shaft fractures and up to 40 degrees for neck fractures.