TUBOS DE PROTECCIÓN Y CANALES PROTECTORAS

The essential difference between a shoe and a boot is that a boot covers the malleoli, while a shoe does not. The foot orthoses is nothing but a boot that has components like supports and wedges to manage different foot symptoms and deformities. These modifications are made of various materials like rubber, foam or leather.

The FO can be divided into a lower part and an upper part (Fig. 7.3).

Components of the Lower Part

Sole: It is the part of the shoe in contact with the ground. The inner part of the sole against which the foot rests is the insole. Bars straps and wedges, which are common attachments to the foot orthoses get their leverage and attachments through the sole and exert their forces (Fig 7.4).

Ball: Widest part of the sole that is located in the region of the metatarsal heads.

Shank: Is the narrowest part of the sole between the heel and ball. The uprights of the AFO attach themselves to a stirrup at the shank region.

Toe Spring: It is the space between the outer sole and the floor, which helps to produce a rocker effect during toe off phase of the gait cycle.

Figure 7.3: Parts of a shoe

Heel: is the posterior part of the sole, which corresponds to the heel of the foot. Since it is the portion where most of the body weight is taken it needs to be resilient and thicker so that it can prevent shoe components from “wearing out” and shift weight to the fore foot.

Upper Part (Also Called Shoe Upper) Components

Quarter: This is the posterior portion of the shoe upper. A high quarter is referred as a “high top” and is used by runners and footballers for greater sensory feedback, and to prevent retrocalcaneal pain.

Heel counter: In sports shoes there is a reinforcement of the quarter posteriorly called a heel counter which provides posterior stability to the shoe and supports the calcaneus.

Vamp: Vamp is the anterior portion of the upper and is often reinforced with a toe box anteriorly. In front is the tongue which protects the upper fore foot behind the lace stays. Extra-depth shoes allow more room inside the shoe for orthotic intervention.

Throat: This is the opening of the shoe located at base of the tongue, through which the foot is inserted.

Toe box: It prevents the toes from suffering trauma when the person kicks as in football. Even normally it is provided in the shoe to avoid stubbing of the toes.

Tongue: This is the part of the vamp which extends down in front of the throat.

Stirrup: This is a piece on the outer sole in the shank region just in front of the heel offering attachment to the metal uprights.

Modifications of the Orthopedic Shoe

The shoe can be modified according to the deformity, disease process or congenital anatomical configuration of the patient to:

Figure 7.4: Modifications to the outer sole

• Maintain the foot in anatomical position

• Treat symptoms of pain burning or fatigability.

• Prevent further deformity

• Afford cosmesis

• Provide symmetry

• Provide a better stance and gait.

Clinical condition Objectives of modifications Modifications Limb shortening Provide symmetric posture Heel elevation:

If < ½ in: internal If < ½ in: external

Heel and sole elevation (if > 1 in) High quarter shoe

Arthritis, fusion, or Improve gait Support High-quarter shoe Reinforced heel instability of or and limit joint motion counters Long steel shank Rocker bar instability of subtalar

joints

Pes plano-valgus Reduce eversion support For children

longitudinal arch High quarter shoe with broad heel, long medial counter, medial heelwedge

For adults:

Medial heel wedge

Medial longitudinal arch support Pes equinus (fixed) Provide heel strike High-quarter shoe

Contain foot in shoe Heel lift & Metatarsal pads or bars Reduce pressure on Heel and sole elevation on other shoe

MT head depending on LLD

Ease putting on of shoe Modified lace stay for wide opening Equalize leg length Wide open throat – open vamp Pes equinovarus Realign for flexible High-quarter shoe

deformity and accommo- Long lateral counter

date a fixed deformity Lateral sole and heel wedges for Increase medial and flexible deformity

posterior weight bearing Medial wedges for fixed deformity on foot

Pes cavus Distribute weight over High-quarter shoe entire foot Restore antero- High toe box

posterior foot balance Lateral heel and sole wedges Reduce pain and pressure Metatarsal pads or bars on MT Heads Molded inner sole

Medial and lateral longitudinal arch support

Calcaneal spurs, Relieve pressure on Heel cushion

calluses and corns painful area Inner relief in heel and fill with soft sponge

Metatarsalgia Reduce pressure on MT Metatarsal pad

heads Support transverse Metatarsal or rocker bar

arch Inner sole relief

Hallux valgus Reduce pressure on 1st Soft vamp with broad ball and toe MTP joint and big toe Relief in vamp with cut-out Prevent forward foot slide Low heel

Contd...

Immobilize 1st MTP joint Metatarsal or sesamoid pad Shift weight laterally Medial longitudinal arch support

Soft vamp

Hammer toes Relieve pressure on painful Soft vamp, extra-depth shoe with areas Support transverse high toe box or balloon patch

arch Metatarsal pad

Improve push off

Foot fractures Immobilize fractured part long steel shank Longitudinal arch support

Metatarsal pad

Metatarsal or rocker bar

ANKLE-FOOT ORTHOSIS (AFO) (FIG. 7.5) Metal Ankle-foot Orthosis

The AFO is a boot to which an ankle joint is fixed through the stirrup. There are metal uprights (medial and lateral bars) ascending up to the calf region.

The components are:

• Proximal calf band with leather straps

• Medial and lateral bars articulating with medial and lateral ankle joints help in control of plantar and dorsiflexion.

Contd...

Clinical condition Objectives of modifications Modifications

Figure 7.5: Ankle-foot orthosis

• Stirrups anchor the uprights to the shoe.

• Other modifications to the shoe, like medial and lateral supports can also be prescribed for the AFO concomitantly.

Ankle Joint

There are five types of artificial ankle joints (Figs 7.6A to E) fit to the AFO, prescribed according to the power of the muscles controlling the ankle. They are:

• Free ankle, given when there is normal ankle power;

• Limited ankle joint is prescribed when the muscles operating the ankle are totally flail and have no power.

• 90° foot drop stop is when the ankle joint allows dorsiflexion but stops short at the neutral position that is at 90 degrees. Thus it does not allow plantar flexion. It is recommended when there is foot drop—when the dorsiflexors are weak and plantar flexors are normal, or when the dorsiflexors are normal or near normal and plantar flexors are spastic.

• Reverse 90° ankle joint: This is an ankle joint which allows plantar flexion but stops short at the neutral position that is at 90 degrees. Thus it does not allow dorsiflexion and is prescribed to prevent a calcaneus deformity.

This happens when plantar flexors are weak, while dorsiflexors are normal.

It is not commonly used.

• Fixed ankle joint: Sometimes the foot needs to be protected and weight is taken off injured portions as in fracture calcaneus when in combination with a weight relieving orthosis it takes the weight off the foot. It is not very commonly used.

Indications

Ankle-foot orthosis is prescribed for,

• Muscle weakness affecting the ankle and sub-talar joints.

Figure 7.6: Types of ankle joints

• Prevention or correction of deformities of the foot and ankle.

• Reduction of inappropriate weight bearing forces.

Dorsiflexor Muscle Paralysis

Aim: To prevent contracture of the Achilles tendon, and to assist dorsiflexion during heel strike a dorsiflexion assist plastic posterior leaf spring AFO can be prescribed that can be inserted in to shoes. This facilitates the client to wear different shoes. The rationale for this option is that the spring prevents the foot from dragging during swing, and permits only slight plantar flexion during early stance, thereby enabling the client to achieve a foot flat position without undue knee flexion. Tension on the Achilles tendon counteracts any tendency to form contracture.

Ankle and Foot Paralysis

This is prescribed to provide stability and reduce gait deviations during the swing and stance phases. A polypropylene solid ankle AFO to be worn with a shoe prevents the foot from dragging during swing; the brace rigidity also prevents ankle dorsiflexion during midstance. Another option is to prescribe a hinged AFO. Adjustable hinges enable the clinician to alter the range of ankle excursion. The limited ankle joint, prescribed quite often, permits ankle movement about a small range, usually 10°-15° of dorsi and plantar flexion. A third option is to prescribe a metal and leather AFO with adjustable ankle joints for plantar flexion and dorsiflexion and corrective straps for valgus and varus deformities. This AFO provides some mediolateral stability.

Spasticity

AFO’s are used in children with cerebral palsy to stabilize the foot during heel strike and foot flat phase. A polypropylene orthosis given as a shoe insert prevents plantar flexion, and also dragging of the toe during the swing phase.

If neglected the foot goes in for equinus contractures and may require injection of Botox or surgery. The sidewalls of the orthosis control pes valgus or varus during early stance.

Limited Weight Bearing

This is a rarer indication for the AFO, to reduce loading on the leg and foot in conditions where the foot needs to be protected (e.g. fracture calcaneus).

There is a socket at the patellar tendon bearing area, which has a weight-relieving brim similar to the socket in the below knee prosthesis. The heel of the foot does not come into contact with the innersole, and a window is provided for a finger to be introduced and confirm this. This enables the weight to be taken higher up at the patellar tendon.

KNEE-ANKLE-FOOT ORTHOSIS (KAFO)