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6
associated with this foot type. However, if the foot is unable to compen-
sate, the patient's gait will be adducted, resulting in characteristic scuff
marks along the medial border of the upper from the heel counter through
to the fore part of the upper and medial sole.
Heel counter wear and distortion
A normal heel counter seen from the back shows little distortion and wear.
There will be mild lateral wear on the plantar aspect of the heel that is
associated with the slight inversion of the normal foot during heel strike.
If excessive subtalar joint pronation is present when the heel strikes
the ground, the heel counter will soon become distorted. The back seam
will lean medially and there will be bulging over the medial border of the
heel. The heel wear mark will be almost directly across the back of the
heel. If the pronation does not take place until after heel strike, the heel
wear will be normal but the upper will be distorted.
When the subtalar joint is supinated, the distortion will be opposite to
the above, however, there will still be a bulge on the medial side as a
result of the heel slipping across the heel seat at heel contact. The upper,
outer, angle of the heel counter may be distorted by the presence of
Haglund's deformity, which is an exostosis caused by compensatory
movement associated with rearfoot varus. If the patient is overweight or
has gross oedema, the heel bulge may be observed on both the medial
and lateral borders, and classically the uppers are distorted in both direc-
tions, too.
Other factors influencing wear
Not all wear on shoes is the result of abnormal function. The most com-
monly seen occupational scuff mark is found on the back of the heel and
is caused by driving. It is important to ascertain the patient's occupation
and social activities in relation to their footwear as unusual wear marks
can be misleading. As
Vernon et al (2004)
point out, shoe wear is a
combination of a multitude of factors. Despite the acknowledgement that
structural and functional variables are reflected in a variety of shoe wear
patterns, there are other factors at play. These may be due to the foot-
wear itself, that is, the materials, the design and the it of the footwear.
The type of activity that is inflicted on the shoes and the duration of this
activity will have an impact on the amount of wear. These two factors are
related to the extent of shoe wear, however, and not to the pattern of
wear.
Vernon et al (2004)
state that identification of all these factors can
aid diagnosis of the underlying foot pathologies in the context of the levels
