Polio leaves many people with feet, walking and spinal deformity problems. Weak muscles are unable to pull against stronger opposite muscles so leading to a lean to the stronger side, shorter or "funny" foot or a difference in leg length.
Let's start by looking at what "normal" muscles of the leg and foot do, then we may see why we have some of the problems we do.
Buttock and stomach muscles are essential for walking leg movements. Bending and straightening rely on other groups of muscles in the legs and feet.When a nerve impulse is received in a muscle fibre, it triggers off a chemical change which shortens the fibre. When a bundle of fibres contract together it pulls on the bone to which it is attached causing it to move. Muscles return to their original length when the nerve impulses stop. They are assisted by opposing muscles which return the bones to their original positions.
Muscles pull downwards, balanceing the upright body. Posture that is out of alignment due to loss of muscle and bony distortion, increases the stresses on balance and remaining muscles, tendons and joints.
Postural changes can include:
or a combination of any of these.
Uneven leg length or arm length and even stunted
growth of bony rib, pelvis can occur due to polio, leading to uneven shoulders
and hips, excessive gait (walking) swing and body twisting to compensate.
Exaggerated body movements may be necessary to compensate for lost muscles
to enable leg and body movement. Straighten-ing up of hip and shoulders
by a shoe raise (adding a few cm at a time) can alleviate back pain.
Pain can occur in neck, back , hip knee, foot due to leg length discrepancy.
When we walk, muscles and tendons at the front
of the foot lift the toes and foot up. The heel and forward movement
utilises muscles and tendons at the back of the foot and leg.
Missing muscles due to polio can cause odd shaped
feet depending on the pull. A high instep or cavus foot can be caused
by paralysis of anterior tibial (shin) muscles or Achilles tendon (going
down at the back to the heel).
Rolling in or outwards of the foot when walking
may also occur. This can become more exaggerated with age and time, requiring
surgical boot support &/or caliper to lessen strain and callouses.
Paralysis of posterior tibial (some of the calf
muscles) allows the underneath arches to sag causing a flatfoot.
Complete paralysis of foot muscles can result
in a flaccid (no movement) foot.
Uneven pull can cause claw toes, hammer toes,
bunions and corns.
Sometimes the uneven pull may result in the need for high heels to accommodate unusual foot-shape. These people can not wear low shoes as the bones are set in this way and high heels actually help to retain body balance.
Some of you may have had osteotomies and arthrodesis
previously. (operations to fuse or change shape of the foot)
This could involve cutting out sections of bone and/or inserting bone somewhere
All of these abnormalities can result in longterm wear and tear on joints, muscles, tendons and ligaments. Eventual outcomes include, painful joints, arthritis, further weakness and loss of power and sensation. Joint replacement or stabilisation may be necessary eg fusions of ankle, toes, knees, spinal joints; hip and knee replacements.
External supports include shoe raises, in-shoe orthosis, calipers, surgical shoes, knee braces, abdominal corsets; walking sticks and frames; crutches and wheelchairs. These require proper expert fitting through orthotic and wheelchair clinics, physio and OT services. In-home alterations such as handrails, toilet raisers, shower and bath accessories, raised adjustable home seating (maybe with arms), ramps, mobile trays, pick-me-uppers, alarm bells, phones in case of falls, wheelchair hoists, may be needed.
Many of these items are available through local
hospital OT department, Silver Chain or central specialised centres of
excellence. For further information on how to access these in WA
ring Tessa at the Polio Office or speak to your doctor.
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