The biomechanics of foot and ankle problems after stroke and the effects of orthotics on such problems

Forghany, S

Abstract

Stroke is the leading cause of adult disability and -50% of people with stroke suffer foot deformities which influence walking. The aim of this study was to investigate foot and ankle biomechanics, posture, multi-segment kinematics
and plantar pressure in people with stroke and explore the possible causes and functional consequences of any abnormalities.
A cross-sectional survey of the static foot posture in 72 people with stroke showed that one-third had abnormal and asymmetrical foot posture with almost equal numbers having pronated and supinated affected foot associated with limited walking ability.
Stance phase foot and ankle biomechanics were quantified using a multisegment foot model on the affected side of twenty stroke and fifteen healthy age-matched subjects. The role of neuromuscular impairments in biomechanical abnormalities was characterised by concurrently measuring the electromyography and spasticity of major posterior and anterior lower leg muscles and the dynamometric measures of plantarflexor stiffness, plantarflexor and dorsiflexor strength and ankle proprioception.
The following abnormalities in people with stroke were found: Reduced range of motion across most segments and planes
A more pronated foot
A less supinated foot during propulsion
Deficit in the foot rocker function
Disruption in the timing of joint motion
Change in the coupling mechanisms
Greater variability
The changes in pronation and supination were associated with limited walking
ability and soleus spasticity and plantarflexor stiffness.
The work also investigated the effects of lateral wedges orthoses on the eight lower leg muscles to understand the interactions between foot and ankle biomechanics and neuromuscular function. In eight healthy subjects, there was
a trend for peak muscle length, excursion and lengthening velocity to increase when wearing lateral wedges orthoses. The observed changes strongly support a follow-on study in a stroke population to explore the effects of lateral wedge
orthoses on muscle length and lengthening characteristics

Citation

Forghany, S. The biomechanics of foot and ankle problems after stroke and the effects of orthotics on such problems. (Thesis). University of Salford

• Thesis Type: Thesis
• Deposit Date: Oct 3, 2012
• Award Date: Jan 1, 2009