Week 4/5 - Ankle Anatomical Variants Flashcards
What is the difference between a deformity and a disorder?
Deformities are permanent, structural deviations from normal. Disorders are irregularity or disturbance of natural function such as illness or ailment
What does a forefoot valgus look like?
When the forefoot is everted relative to a neutral rearfoot
What is a global forefoot cavus?
Plantarflexed forefoot, essentially a forefoot equinus
How do deformities in the sagittal plane affect the foot? Examples?
Limit dorsiflexion/plantar flexion at each joint. Includes pes equinus, plantar flexed first ray, pes calcaneus
What motion do frontal plane deformities limit?
Inversion and eversion
What are some examples of frontal plane deformities?
Forefoot varus/valgus, rearfoot varus/valgus, forefoot supinatus
What motion do transverse plane deformities affect?
Abduction and adduction
What are some examples of transverse plane deformities?
Adductus (forefoot or entire foot), abductus
How do we make an orthotic using root theory?
Accommodate for rigid deformities, correct flexible deformities
How do we make an orthotic using tissue stress theory?
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
What are some potential causes of a plantar flexed first ray?
Weakness of the gastroc/soleus complex, excessive strength of the peroneus longus, weak tib ant, compensation for rigid rearfoot varus, neurological ocnditions
What are the differences in pathomechanics for a fixed and flexible plantar flexed first ray?
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
How does treatment of a rigid and flexible plantar flexed first ray differ?
With a rigid deformity, we aim to reduce the need for compensatory supination. With a flexible deformity, the reduce the need for compensatory pronation
What is pedorthic treatment for a dorsiflexed first ray?
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
What potential conditions could result in a compensatory dorsiflexed first ray?
Rigid rearfoot valgus
If a patient presented with a rigid dorsiflexed first ray, what is a potential compensation we could see?
Excessive rearfoot eversion as the hallux is not in position to reach the ground to reduce eversion and excessive pronation
What measurement is used to classify a pes equinus?
Amount of dorsiflexion. Less than 10 degrees during gait qualifies as pes equinus
What are some structural reasons for a pes equinus to develop?
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)
What are some other (soft tissue, trauma) reasons that could cause a pes equinus to develop?
Soft tissue: congenital shortening of plantar flexors, CP, other neuromuscular spasms
Trauma: restrictions to periarticular connective tissue from trauma or immobilization
What are some compensations we could see with a pes equinus foot?
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
What would pedorthic treatment consist of for a pes equinus foot?
Heel lifts, footwear, footwear mods, orthoses
What is a pes calcaneus foot?
Limited plantar flexion at the ankle, very uncommon. Rarely treated by pedorthists, often need surgery
What is an uncompensated rearfoot varus?
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
What is a partially compensated rearfoot varus?
Tibial varum and/or inverted calcaneus with some STJ pronation/rearfoot eversion but not enough to bring the medial heel to the ground
What is a compensated rearfoot varus?
Equal amounts of tibial varum/rearfoot inversion and STJ pronation/rearfoot eversion to compensate so the heel becomes vertical
What are the pathocmechanics of a rearfoot varus?
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
What is pedorthic treatment for a rearfoot varus?
Controlling compensatory motions, accommodating a rigid rearfoot varus deformity. Can use MLA support, or a rearfoot varus (medial) post
What would we expect to see in an evaluation of a rigid forefoot varus?
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
What are some pathomechanical issues that could result from a forefoot varus?
Talus being maintained in an adducted position, abductory twist at heel lift
What is a forefoot supinatus?
Flexible forefoot varus
