Cath Lab Digest

Given the difficulties of managing neuromuscular conditions in the lower extremity, these authors offer key insights on the use of orthoses, shoe modifications and bracing devices for treating dilemmas ranging from lateral ankle instability to dropfoot.

     The neuromuscular lower extremity presents a variety of challenges for the podiatrist, pedorthist, orthotist and physical therapist. Accordingly, one should have a strong understanding of the role of conservative stabilization for patients who have neurological deviations and deficits that may be caused by a variety of conditions.

     These conditions include Charcot-Marie-Tooth disease, hemiplegic cerebral palsy, spastic diplegia, quadriparesis, peroneal nerve injuries, post-polio syndrome and cerebrovascular accidents.

     It is sometimes difficult to separate and address specific joints when treating the neuromuscular foot as the gait cycle involves closely related interplay among all of the joints of the lower extremity, especially the complex joints of the foot and ankle.¹

     When it comes to stabilizing the neuromuscular foot, providers may utilize foot orthoses and shoe modifications as well as bracing devices such as ankle-foot-orthoses (AFO) and knee-ankle-foot-orthoses (KAFO).

     The basic objectives of shoe and bracing treatment in these cases include:

• stabilizing a weak or flaccid foot-ankle complex by compensating for weak muscles or muscle groups;

• correcting passively correctable deformities;

• preventing or slowing the progress of further deformity; and

• regulating or reducing motor tone.

     Essentially, the purpose of treatment is to enhance normal movement while correcting abnormal gait patterns and increasing the efficiency of ambulation.

What You Should Know About Lateral Ankle Instability

Many off-the-shelf options are available for the conservative treatment of mild to moderate ankle instability. Off-the-shelf braces include elastic and nylon lace-up supports as well as pre-molded, plastic, hinged braces. Not only can these braces help prevent unwanted hindfoot and ankle inversion, they allow relatively unrestricted dorsiflexion and plantarflexion of the foot and ankle.

     When it comes to patients with lateral ankle instability, recommended off-the-shelf footwear includes high-top athletic shoes or boots that cover the ankle and provide extra support; cross-trainers or hiking shoes with a stable base and good medial-lateral stability; or neutral or anti-supination walking or running shoes.

     The majority of walking and running shoes are made to prevent overpronation. These anti-pronation shoes often have medial wedging incorporated into the heels as well as extra support and stiffness on the medial side of the shoe. This type of shoe is contraindicated for patients with lateral ankle instability as it will only serve to exacerbate the problem.

     If the off-the-shelf shoe is not sufficient, one can modify it to provide a wider, more stable base of support. ² Providers can do this by adding a lateral heel flare or outrigger to the sole of the shoe. If this is not sufficient, one can add a lateral buttress or stabilizer. The buttress extends from the floor approximately 4 to 5 inches up the side of the shoe and covers the lateral hindfoot and midfoot. It is made of a stiff material, usually ½ inch to 1 inch thick, and prevents lateral rolling of the hindfoot. One may also reinforce the internal counter of the shoe with fiberglass for added strength and stability.

     One goal of any foot orthosis or AFO is to maintain correct anatomic alignment of the calcaneus in order to reduce hindfoot and ankle medial-lateral instability. This is especially true when dealing with lateral ankle instability. Any sort of AFO will decrease postural sway in stance phase. ³

     The foot orthosis for this condition will typically have a deep heel cup in order to maximize contact with the heel and control of the heel. Often, a lateral heel wedge will be built into the device. For chronic ankle instability, a laterally posted foot orthosis is not usually sufficient and an AFO is required.