Ankle Orthoses

Question 1

Types of AFO designs

Answer 1

Conventional

Thermoplastic

Floor Reaction

Anterior Shell & PTB

Question 2

Rigidity of thermoplastic AFO is influenced by a variety of factors

Answer 2

Type of plastic

Thickness of plastic

Trimlines

• Anterior to malleoli results in increased A-P and M-L rigidity
• Posterior to malleoli - Posterior leaf spring design, flexible at the ankle with somewhat of a dorsiflexion spring assist, does not maintain stability of hte ankle

Corrugations vacuum formed in place- carbon fiber inserts or rope modifications

Question 3

Advantages of Conventional AFO

Answer 3

Dorsi/plantarflexion ROM easily adjusted

Limited skin contact

Edema accomodated

Permanent shoe attachment = compliance when wearing shoe

Question 4

Disadvantages of Conventional AFO

Answer 4

Heavy

Shoes not easily changed

Cosmetics

Mediolateral control of ankle/foot not as good as in thermoplastic

Question 5

Advantages of thermoplastic AFO

Answer 5

Lightweight

Shoe easily changeable

Cosmetically acceptable

Total contact increases control

Knee stability readily influenced by minor changes in orthosis or sole of shoes

Question 6

Disadvantages of thermoplastic AFO

Answer 6

Limited Adjustability

Rigidity can not be increased

Fixed heel height

Intimate fit does not accommodate edema or changes in volume

Localized pressure and callus formations may occur over time

Insensitive skin must be closely monitored for breakdown

Question 7

Contraindications for articulated thermoplastic AFO

Answer 7

Uncontrolled spasticity- motion at ankle increases spasticity

Severe pronation in midstance from uncontrolled tibial internal rotation

Genu valgus or varus deformities

Over lengthening of the Achilles tendon

Question 8

Floor Reaction

Answer 8

1

Question 9

Floor Reaction2

Answer 9

1

Question 10

Anterior shell/PTB Indications

Answer 10

Provides rigid ankle support

Charcot joint, severely painful

External support for tibial fractures (dsital 2/3 only)

Additional support of ORIF (open rediuction internal fixation) of tibia, distal to tibial tubercle

Post operative fusions of the ankle

Avascular necrosis of the talar body

Question 11

Anterior shell/PTB

Answer 11

1

Question 12

Types of Conventional AFO stirrups

Answer 12

Solid - does not allow for shoes changes, length dependent on m-l stability

Split - allows detachment of uprights, shoe exchange possible, can be incorporated into a plastic foot section so that patient no required to modify shoes to accommodate stirrups/uprights

Round - attached directly to uprights without ankle joints
- results in axis distal to anatomical axis

Question 13

Indications for limited ROM joints

Answer 13

Permits limited plantar/dorsiflexion as desired

Indicated to limit painful ROM

For weak muscle control

Question 14

Contraindication to Dorsiflexion assist (Klenzak)

Answer 14

Spring dorsiflexion assist may trigger spastic gastroc-soleus

You plantar-stop instead for foot drop/dorsi weakness

Question 15

Indications for Dorsiflexion Stop

Answer 15

Free plantar flexion

Active dorsiflexion, absent plantarflexors

Stabilize against undesirable dorsiflexion on later half of stance phase

Prevents early knee flexion

Question 16

Indications for Plantarflexion Stop

Answer 16

Unlimitied