Article

Lateral wedge orthoses are often prescribed to correct varus deformity after
stroke. Spasticity is implicated in varus deformity and is caused by
velocity-related muscle length changes, so a lateral wedge may affect spasticity
by manipulating foot and ankle kinematics which, in turn, may alter the length of
these muscles. We sought to test this theory in healthy participants. Eight
volunteers walked with no wedge and with lateral wedges of 5 and 8.5 degrees in
both shoes. Qualysis motion capture system collected kinematic data and SIMM
musculoskeletal modeling software calculated muscle tendon length of
plantarflexor and peroneal muscle groups using 3-D ankle and knee joint angle
data. The wedges increased ankle eversion (p < 0.0001) and total excursion of
tibialis posterior, peroneus longus and brevis by 13-29% (p < 0.05). Muscle
length of peroneus longus and brevis increased by <1% (p < 0.005). Potentially
clinical meaningful effects were found for tibialis posterior (15%), peroneus
brevis (23%) and peroneus tertius (13%). Further research is required to be
conclusive and to explore the effects of lateral wedge orthoses in patients with
stroke. If such changes are seen in people with stroke, a change in orthotic
prescription practice could be indicated as lateral wedge orthoses may exacerbate
spasticity.

Langue : ANGLAIS