what-when-how
In Depth Tutorials and Information
7
to the foot. This increases the moment arm relative to the rearfoot joints
and thus the eversion at the rearfoot.
The flare may be used as an alternative to a lateral wedged insole to
reduce knee varus moments and thus loading in the medial knee com-
partment, however, it is more unsightly than the foot orthosis equivalent
and thus compliance may become an issue. It may also be used in cases
of recurrent lateral ankle sprain, to ensure that the rearfoot pronates rather
than supinates at initial contact.
A flare should also be considered as a feature on a patient's existing
footwear that you may want to consider as part of the aetiology of the
reported foot or lower limb problem. Some retail footwear may have some
flare for cosmetic reasons but this will alter foot movements and subse-
quent foot function, and may elicit medial foot pain as a result of increased
pronation of the foot.
In cases where footwear does have a lateral flare, such as some
running footwear, the flare may be constructed of soft material such that
it deforms quickly under load. This may negate any effect it might have,
and in fact is deliberate so that the stiffer material on the medial side of
the heel can have a wedging effect on the heel.
The medial flare will have the opposite biomechanical effect to the
lateral, increasing inversion moments at the rearfoot and varus moments
at the knee. It will thus increase resistance to pronation and be an alterna-
tive or additional means of controlling foot motion.
Heel elongations
An anterior-medial heel extension, or Thomas heel, provides medial arch
support complementing orthotic therapy in pronated foot types, painful
arthropathy and Charcot deformity. A lateral Thomas heel supports the
cuboid region. A medial heel extension can affect plantar pressure by
shifting it more laterally than a standard heel and it prolongs the duration
of pressure over this area (
Figure 7.5
).
Rocker soles
Rocker soles are the commonest sole modification and are considered
the most effective forefoot offloading method, potentially reducing move-
ment and pain, compensating for loss of motion and reducing forefoot
pressure, which is particularly useful in patients with diabetes and a history
of ulceration or identified excessive forefoot pressures (
Dahmen et al
2001
). They have been found to be useful in those with transmetatarsal
amputations (
Mueller et al 1997
). Functioning on a rigid sole, they rock
the foot without the foot flexing from heel strike to toe off. The design
features a lat or negative heel and midfoot area with a distinct toe spring
