Unit 4: Foot Orthotics

Question 1

What are foot orthotics defined as

Answer 1

Inserts that are placed into a patient’s shoes, adaptions to a patient’s shoes and bespoke footwear

Question 2

Applications of foot orthoses

Answer 2

Congenital abnormalities: club foot, pes cavus, planovalgus
Diseases: polio
Inflammatory conditions: RA
Metabolic conditions: gout
Degenerative conditions: OA
Diabetes
PVD

Question 3

Describe club foot

Answer 3

Equinovarus. Unknown cause but associated with severe neurological conditions e.g. spina bifida

Question 4

What are the 2 forms of club foot

Answer 4

Mild and severe
Mild: postural, can be corrected by manipulation, associated with breech birth
Severe: fixed, requires surgery to salvage foot function

Question 5

What are pes cavus and planovalgus

Answer 5

Arched foot and flat foot: can arise spontaneously or in association with neuro disorders (cerebral palsy)

Question 6

What is poliomyelitis caused by

Answer 6

Viral infection of the anterior horn cells of the spinal cord. Usually water borne

Question 7

Consequences of poliomyelitis

Answer 7

Foot deformities and foot length discrepancy

Sensation remains normal

Question 8

Which joints does RA typically affect

Answer 8

Small joints of the hands and feet

Question 9

Why does foot trauma tend to take longer to heal than hand trauma

Answer 9

Vascular supply is not as good

Question 10

Causes of gout

Answer 10

Abnormal purine metabolism leading to high uric acid levels e.g. due to treatment with antimetabolite drugs in cancer patients

Question 11

Why does diabetes mellitus lead to foot trauma

Answer 11

Ineffective insulin control leads to peripheral neuropathy. Causes insensitivity and disrupted microvascular function

Question 12

What 2 things is PVD commonly associated with

Answer 12

Diet and smoking

Question 13

What are the 3 types of functional disorder

Answer 13

Deformity
Instability
Insensitivity

Question 14

What are the objectives of orthotic treatment of irreducible deformity

Answer 14

Accommodate the deformity to obtain acceptable distribution of the weight-bearing forces
Compensate for loss of ankle/foot joint motion

Question 15

What problems can irreducible deformity cause

Answer 15

Abnormal initial contact with the ground
Abnormal plantar pressure distribution
Abnormal, generally restricted, movements of the ankle and joints during dynamic activities

Question 16

How is abnormal contact with the ground corrected

Answer 16

‘Fill-in’ the space between the foot and ground created by the deformity

Question 17

How are abnormal plantar pressure distributions treated

Answer 17

Moulding the orthosis accurately to the foot shape, taking into account pressure sensitive and pressure tolerant tissue areas

Question 18

How should abnormal ankle joint movement be compensated for

Answer 18

Designing an orthosis which deforms in a controlled manner to simulate normal joint movement

Question 19

What are the objectives of treating instability with an orthosis

Answer 19

Prevent abnormal joint movements resulting from the instability
Compensate for any loss of ankle or foot joint function

Question 20

How is normal initial foot contact re-established

Answer 20

Position and hold the ankle in normal plantigrade alignment

Question 21

How is abnormal plantar pressure treated

Answer 21

Use an orthosis that resists collapsing of the foot

Question 22

What factors contribute to tissue breakdown

Answer 22

Direct tissue pressure
Shear stress
Rate and duration of tissue loading

Question 23

How to reduce direct pressure

Answer 23

Use a moulded interface

Question 24

How to minimise shear stress

Answer 24

Reduce MTP extension between heel-off and toe-off by stiffening the support surface. Should also incorporate a heel cushion and rocker modification

Question 25

Problems caused by fixed equinus foot deformity

Answer 25

Initial ground contact with the forefoot Excessive pressure on the forefoot because of reduced area of support Loss of normal ankle joint function

Question 26

Elements of a foot orthosis designed to treat foot equinus

Answer 26

Built-up heel: simulates plantigrade ankle position Moulded insole: redistributes pressure Cushion heel: simulates plantarflexion at heel contact Rocker sole: compensates for loss of dorsiflexion, assists roll-over prior to toe off

Question 27

Problems associated with fixed varus deformity

Answer 27

Initial contact on the lateral aspect of the heel Excessive pressure on the lateral aspect of the plantar surface Loss of subtalar joint function

Question 28

Elements of a foot orthosis designed to treat fixed varus

Answer 28

Medial sole Built up heel Moulded insole: shaped to redistribute pressure across the plantar surface

Question 29

Problems caused by an unstable pronating foot

Answer 29

Foot collapses into valgus = excessive pressure on medial aspect of foot Absent subtalar supination/pronation = less functional gait pattern

Question 30

Elements of a foot orthosis designed to treat pronating foot (DIRECT methods)

Answer 30

Moulded arch support to hold the medial arch | AFO for severe cases: applies 3-point force system across the subtalar joint

Question 31

Indirect methods of treating pronating foot

Answer 31

Wedge/float the heel of the shoe to promote supination at heel contact Moulded heel cup

Question 32

Problems caused by toe clawing

Answer 32

Excessive pressure under the metatarsal heads as the heel leaves the ground to initiate push off Loss of final toe extension movement

Question 33

Elements of a foot orthosis designed to treat toe clawing

Answer 33

Metatarsal support: applies corrective force for realignment | Stiffener in the sole of the orthosis: resists excessive dorsiflexion, reduces loss of push-off

Question 34

What are the early indicators of high pressure areas

Answer 34

Corns and callousing

Question 35

What methods are used to identify patients at risk of tissue breakdown due to high pressure areas

Answer 35

Barefoot assessment using pressure platforms | In-shoe pressure monitoring systems

Question 36

How are high pressure areas treated

Answer 36

Adapted plaster of Paris cast | Extra-depth insole with associated boot/shoe

Question 37

Describe the structure of the extra-depth insole

Answer 37

High density closed cell foam base Intermediate medium density layer Thin top cover of soft leather or neoprene