Osteochondroses
are bone disorders which affect the maturing skeleton. The ossification
centers undergo aseptic vascular necrosis, resorption and then bone
repair. The ossification centers affected by this condition (osteochondroses)
becomes temporarily softened and is prone to deformity from pressure.
They can occur at various sites in the body. The most commoly occurring
sites in the foot are listed below. Kohler's, Freiberg's and Sever's
are used as examples
Kohler's
Disease: osteochrondrosis of the navicular
This
condition was first described by Kohler in 1908. The developing
ossification center of the navicular becomes compressed by weightbearing
forces. Radiographically the involved area may appear more sclerotic
with a characteristic anteroposterior narrowing of the navicular.
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Kohler's
disease - avascular necrosis of the navicular; tha navicular
becomes flattened, sclerotic and irregularly bordered (AP
view)
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The
same foot seen here on an oblique view. Kohler's is seen
most commonly in boys aged 3-6 years
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Within
this AP view of both feet, the right navicular is noticably
narrower and irregular compared to the left foot.
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Note
the navicular on the right appears narrow indicative of avascular
necrosis
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Lateral
View. The navicular appears small relative to the other tarsal
bones.
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AP
view.
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AP
and Lateral Oblique veiws. The navicular appears flattened.
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Freiberg's
Infarction
This condition
was first described by Freiburg in 1914 as an infarction of the second
metatarsal head. Freilburg's has the potential to affect any of the
lesser metatarsal heads. Radiographically a characteristic flattening
of the head of the metatarsal can be viewed. This characteristic feature
is known as the 'egg crush' appearance. Furthermore the metatarsal
head is prone to flaring and a trumphet like appearance of the metatarsal
head becomes evident upon xray.
Smilies
X-ray : 5 Stage Classification
Stage
1 Epiphyseal fissure fracture
Stage
2 Central portion of Bone Reabsortion
Stage
3 Metatarsal head begins to flatten
Stage
4 Intra &endash; articular loose body
Stage
5 Complete flattening of the metatarsal head
Freiburg's
affects the metatarsal heads, generally due to traumatic
disruption of the physeal blood supply.
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Most
commonly, the second metatarsal is affected. Seen most frequently
in girls 13 years and older.
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Sever's
Disease
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Sever's
disease - is a traction apopysitis of the calcaneus and
not
a
osteochondrosis. A healthy, undiseased apophysis of the
calcaneus appears sclerotic and fragmented with an increase
in bone density; for this reason radiographs are not indicated
and diagnosis is made solely on clinical findings. It is
seen most commonly in boys aged 8-14 years or greater.
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NOTE:
osteochondroses can also be located at any point of growth.
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