Over
80% of adult stress fractures involve the tibia, fibula, metatarsals
and calcaneus. Stress fractures in children have a different clinical
presentation. Stress fractures of the navicular, other tarsal bones
and sesmoids occur less frequently than the metatarsals and calcaneus.
Most navicular stress fractures occur in the sagittal plane and
involve the medial third of the navicular.
Radiographic
Diagnosis
Xrays
are normally used in the acute phase. Metabolic changes at the site
of the fracture allows isotope bone scans to detect the injury as
early as 24 hours. Stress fractures differ in their appearance at
different locations. Calcaneal fractures tend to present with a
curvilinear area of condensation radiographically. Metatarsal fractures,
when visible on x - ray typically present with slight callus or
a lucent line in the cortex. Fractures in the first metatarsal tend
to involve the cancellous bone proximally and periosteal reaction
is minimal. Typically isotope studies and tomography are required
to conform the suspected stress fracture. Other imaging techniques
have also been used including magnification, xeroradiography and
more recently MRI.
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Stress
fracture of the tibia.
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For
some excellent images of calcaneal stress fractures, click
here (MRI images) and here (plain
film radiography).
