Week 4/5 - Ankle Anatomical Variants

Question 1

What is the difference between a deformity and a disorder?

Answer 1

Deformities are permanent, structural deviations from normal. Disorders are irregularity or disturbance of natural function such as illness or ailment

Question 2

What does a forefoot valgus look like?

Answer 2

When the forefoot is everted relative to a neutral rearfoot

Question 3

What is a global forefoot cavus?

Answer 3

Plantarflexed forefoot, essentially a forefoot equinus

Question 4

How do deformities in the sagittal plane affect the foot? Examples?

Answer 4

Limit dorsiflexion/plantar flexion at each joint. Includes pes equinus, plantar flexed first ray, pes calcaneus

Question 5

What motion do frontal plane deformities limit?

Answer 5

Inversion and eversion

Question 6

What are some examples of frontal plane deformities?

Answer 6

Forefoot varus/valgus, rearfoot varus/valgus, forefoot supinatus

Question 7

What motion do transverse plane deformities affect?

Answer 7

Abduction and adduction

Question 8

What are some examples of transverse plane deformities?

Answer 8

Adductus (forefoot or entire foot), abductus

Question 9

How do we make an orthotic using root theory?

Answer 9

Accommodate for rigid deformities, correct flexible deformities

Question 10

How do we make an orthotic using tissue stress theory?

Answer 10

Based on how the deformity stresses surrounding tissues. Ex. how does a plantarflexed first ray redistribute forces of gait, how can we accommodate those forces

Question 11

What are some potential causes of a plantar flexed first ray?

Answer 11

Weakness of the gastroc/soleus complex, excessive strength of the peroneus longus, weak tib ant, compensation for rigid rearfoot varus, neurological ocnditions

Question 12

What are the differences in pathomechanics for a fixed and flexible plantar flexed first ray?

Answer 12

With a fixed deformity, the STJ supinates to compensate to bring the lateral forefoot plantigrade. In a flexible deformity, the first ray is forced into dorsiflexion to realign with the other toes, which could cause greater pronation

Question 13

How does treatment of a rigid and flexible plantar flexed first ray differ?

Answer 13

With a rigid deformity, we aim to reduce the need for compensatory supination. With a flexible deformity, the reduce the need for compensatory pronation

Question 14

What is pedorthic treatment for a dorsiflexed first ray?

Answer 14

Foot orthoses: reduce RF valgus to reduce need for compensatory first ray dorsiflexion, support the arch to increase activity of peroneus longus to help plantar flex the first ray
Footwear: deep toe box to accommodate deformity, avoid stitching near first ray

Question 15

What potential conditions could result in a compensatory dorsiflexed first ray?

Answer 15

Rigid rearfoot valgus

Question 16

If a patient presented with a rigid dorsiflexed first ray, what is a potential compensation we could see?

Answer 16

Excessive rearfoot eversion as the hallux is not in position to reach the ground to reduce eversion and excessive pronation

Question 17

What measurement is used to classify a pes equinus?

Answer 17

Amount of dorsiflexion. Less than 10 degrees during gait qualifies as pes equinus

Question 18

What are some structural reasons for a pes equinus to develop?

Answer 18

Flattened talar trochlea (causes early contact between tibia and talus), wide anterior talar dome (too wide for ankle mortise), and narrowed ankle mortise (talus too wide)

Question 19

What are some other (soft tissue, trauma) reasons that could cause a pes equinus to develop?

Answer 19

Soft tissue: congenital shortening of plantar flexors, CP, other neuromuscular spasms
Trauma: restrictions to periarticular connective tissue from trauma or immobilization

Question 20

What are some compensations we could see with a pes equinus foot?

Answer 20

Excessive pronation, hypermobility of the STJ, accentuated rearfoot eversion, hypermobility of the midtarsal joint, early heel lift, toe to heel or toe to toe initial contact, genu recurvatum

Question 21

What would pedorthic treatment consist of for a pes equinus foot?

Answer 21

Heel lifts, footwear, footwear mods, orthoses

Question 22

What is a pes calcaneus foot?

Answer 22

Limited plantar flexion at the ankle, very uncommon. Rarely treated by pedorthists, often need surgery

Question 23

What is an uncompensated rearfoot varus?

Answer 23

Presence of tibial varum possible and/or an inverted calcaneus with no STJ pronation or rearfoot eversion. Depending on degree of tibial varum, could be walking on lateral foot due to the inability to evert the heel

Question 24

What is a partially compensated rearfoot varus?

Answer 24

Tibial varum and/or inverted calcaneus with some STJ pronation/rearfoot eversion but not enough to bring the medial heel to the ground

Question 25

What is a compensated rearfoot varus?

Answer 25

Equal amounts of tibial varum/rearfoot inversion and STJ pronation/rearfoot eversion to compensate so the heel becomes vertical

Question 26

What are the pathocmechanics of a rearfoot varus?

Answer 26

Pronation causes the calcaneus to evert and talus to adduct/plantar flex, possibly straining CN/TN ligaments. Talus is displaced further with greater rearfoot eversion, which forces the medial column (first 3 rays and navicular) to move anteriorly and abduct away from the 4th/5th rays

Question 27

What is pedorthic treatment for a rearfoot varus?

Answer 27

Controlling compensatory motions, accommodating a rigid rearfoot varus deformity. Can use MLA support, or a rearfoot varus (medial) post

Question 28

What would we expect to see in an evaluation of a rigid forefoot varus?

Answer 28

Rear foot sitting in an inverted position relative to the forefoot. Limited to no midfoot eversion. Excessive calcaneal eversion and STJ pronation to bring the forefoot plantigrade

Question 29

What are some pathomechanical issues that could result from a forefoot varus?

Answer 29

Talus being maintained in an adducted position, abductory twist at heel lift

Question 30

What is a forefoot supinatus?

Answer 30

Flexible forefoot varus