Fractures
of the fifth metatarsal can occur in a variety of locations. Fractures
occurring at the base are usually due to inversion and plantarflexion
injuries which can cause avulsion of the fractured segment. X-rays
of a sprained ankle should always include the base of the fifth metatarsal
to ensure that a fracture is not missed.
Jones'
fractures are stress fractures of the diaphysis which commonly present
in young athletes or post-operative patients who have altered weightbearing
patterns.
Fractures
can also occur in the shaft as a direct result of trauma.
TRAUMA:
EPIPHYSEAL FRACTURES
Salter
And Harris Classification
TYPE
1 Separation of the epiphysis from the metaphysis
TYPE
2 Line of fracture passes through the growth plate and then a
portion of the
Metaphysis
TYPE
3 Line of fracture involves the growth plate, epiphysis and adjacent
joint
TYPE
4 Line of fracture involves the joint, the epiphysis, the growth
plate and the
Metaphysis
TYPE
5 The growth plate is crushed, involving adjacent structures
(Salter,
1970)
Fracture
of shaft
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Avulsion
fracture
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Fracture
of shaft not visible on A-P (left) only obvious on oblique
shot (right)
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It
is important that an avulsion fracture (above left) is distinguished
from an accessory bone (eg. os peroneum - above right) and
also from normal growth plates. An avulsion fracture enters
the fifth met-cuboid joint space whereas growth plates do
not.
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5th
Metatarsal fracture
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Lateral Oblique view -fracture at styloid process
C/0
Latrobe podiatry clinic
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Further
information regarding 5th metatarsal fractures can be obtained from
the following external web pages:
http://www.pcpm.edu/Christman/Cases/Met5Fx/Met5AvFx.htm
http://www.pcpm.edu/Christman/Cases/Met5Fx/Met5Fxs.htm
Reference:
Salter, RB, Textbook of Disorders and injuries of the Musculoskeletal
System. Williams and Wilkins. Baltimore, 1970.
