- Discussion:
- hyperpronation refers to the inward rotation of the foot during gait;
- the term is vague and probably should be replaced by precise descriptions of the relative positions of the hindfoot
and forefoot during
gait;
- w/ hyper-pronation, there is an inability of the foot to supination during mid to terminal
stance phase;
- diff dx:
- hindfoot valgus causes the talar head to move in a medial and plantar direction (in children w/
CP
the talar head can touch the floor);
- to compensate the mid-foot (talo-navicular joint) must actually supinate (spin laterally and superiorly)
which leaves the talar head uncovered;
- hyperpronation does place stress on the midfoot, but does not become a significant problem unless the patient
develops a heel cord contracture;
- w/
heel cord contracture, the already stressed midfoot must now compensate for loss of dorsiflexion at the ankle joint;
- the result is a midfoot break, either at the talo-navicular joint or the navicular-cuneiform joint which leads to chronic pain;
- is associated w/
flat feet as well as both
tibia vara (? and genu valgum);
- Exam:
- patient is viewed from behind and relative ankle-subtalar valgus is noted;
- patient is asked to rise up onto toes and amount of inversion is noted;
- ankle motion is noted (w/ knee extended and hindfoot in varus);
- this is compared to dorsiflexion of the opposite ankle;
- amount of talar head coverage and uncoverage is noted;
- Treatment:
- its essential to determine the cause of the hyperpronation deformity;
-
equinus contracture:
- patients w/
flat feet often have a more horizontal sub talar axis which allows a relative increase in
sub-talar dorsiflexion and plantarflexion;
- this may result in relative decrease in ankle dorsiflexion;
- in the presence of a relative heel cord contracture, the patient should be started on a diligent course of stretching;
- this will take the stress off the midfoot, and in most cases will relieve pain;
- leg length descrepancy:
- may cause a relative equinus contracture and hyperpronation of the foot;
- treated w/ heel lift on contra-lateral side;
-
foot orthotics:
- are generally very expensive and and in many cases ineffective;
- generally orthotics should not be prescribed until the heel cord contracture is corrected;
- note that after paying several hundred dollars for a pair of orthotics many patients will be embarased
to admit that the orthotics don't work;
