26 - Everted Forefoot Deformities Flashcards
Types of everted forefoot deformities
- Forefoot valgus
- Plantarflexed 1st ray
- Dorsiflexed cuboid
Forefoot valgus diagram
There are two types – flexible (total) forefoot valgus
(7 degrees) or rigid plantarflexed 1st ray
Total forefoot valgus
- Everted position of the forefoot relative to the rearfoot at the level of the MTJ.
- All of the metatarsals are on the same everted plane with one being more inferior to five
Possible etiology of total forefoot valgus
o Due to excessive frontal plane valgus torsion of the head and neck of the talus. At birth, the head and neck of the talus are in a varus rotation which quickly corrects by undergoing a valgus rotation.
o If the compensation is excessive, the MTJ everts relative to the STJ
Lateral column in total forefoot valgus
- Inversion of the lateral column of the forefoot must occur to allow the forefoot to purchase the ground during midstance and propulsion
2 forms of compensation
o Flexible(total)forefoot valgus (7°)
The compensation for a forefoot valgus follows the acronym LASSO
KNOW THIS
o LAS is MTJ longitudinal axis supination – this occurs with the flexible FF valgus
o S is STJ supination and O is MTJ oblique axis supination – These occur with rigid FF valgus (after first undergoing LAS)
LASSO o L = longitudinal o A = axis o S = supination o S = STJ supination o O = MTJ oblique axis supination
Flexible (total) forefoot valgus
- Sufficient flexibility exists within the long axis of the MTJ (LMTJ) to equal the degree of FF valgus, and allows the lateral column of the foot to reach the ground.
- Leads to severe MTJ instability during propulsion even though the heel is vertical in RCSP
RCSP in flexible (total) forefoot valgus
KNOW THIS
- The heel is vertical in RCSP*
- In flexible FF valgus, the heel remains vertical (the STJ does not need to compensate for the deformity), but the medial arch drops
Flexible (total) forefoot valgus compensation details
- All of the compensation occurs around the long axis of the MTJ
- It is a hypermobile foot because the MTJ is supinated
- We know that the supinated position of the MTJ is the unstable position of the forefoot (MTJ pronation is the stable position-cuboid locked on dorsal lip of calcaneus)
Signs and symptoms of flexible (total) forefoot valgus in the skin
o Medial heel callus
o Callus sub 2 ( 5 degrees)
o Corn 2, 4, 5 toes
Signs and symptoms of flexible (total) forefoot valgus in the muscle and fascia
o Posterior tibial strain
o Plantar fasciitis
Signs and symptoms of flexible (total) forefoot valgus in the bones
o Sinus tarsi syndrome o Cuboid syndrome o 1st met - cunei exostosis o Bunion o Tailor’s bunion o Heel spur
Signs and symptoms of flexible (total) forefoot valgus in the gait
o Abductory twist
o Late midstance pronation
o Mild lateral instability may occur
Signs and symptoms of flexible (total) forefoot valgus in the foot type
KNOW THIS
**Severe flatfoot **
This means there will be strain on the MEDIAL ankle structures
Rigid (total) forefoot valgus
- If the amount of FF valgus is > 7 degrees, the LMTJ cannot fully compensate.
- STJ supination occurs first.
- If this is insufficient to get the lateral column to the ground, the OMTJ supinates.
RCSP in rigid (total) forefoot valgus
KNOW THIS
Heel is in varus in RCSP
This leads to a HIGH ARCH
Signs and symptoms of rigid (total) forefoot valgus in the skin
o Lateral heel callus
o Callus sub 1 & 5
o Corn 4 & 5 toes
LATERAL instability present
Signs and symptoms of rigid (total) forefoot valgus in the muscle or fascia
o Plantar fasciitis
o Achilles tendonitis
o Functional equinus
Signs and symptoms of rigid (total) forefoot valgus in the bones
o 1st met - cunei-exostosis o Hallux limitus o Increased shock in gait o Retrocalcaneal exostosis o Heel spur
Signs and symptoms of rigid (total) forefoot valgus in the gait
o Normal progression
o Resupination at midstance
Signs and symptoms of rigid (total) forefoot valgus in the foot type
*KNOW THIS
Stable cavus
LATERAL INSTABILITY
Two types of deformities seen with a plantarflexed 1st ray
- Structural
- Positional
Structural deformity - plantarflexed first ray
KNOW THIS
- AKA rigid plantarflexed 1st ray
- Congenital
- Cavus foot
- Difficult to dorsiflex 1st metatarsal head to level of 2nd metatarsal head with manual pressure with STJ neutral – lesser meta heads are on the same parallel plane
- 1st ray R.O.M. is normal (10 mm), but more in plantarflexion.
- RCSP of varus (compensates just like a rigid FF valgus)
Foot type in structural plantarflexed 1st ray
KNOW THIS
***** Cavus foot **
RCSP in structural plantarflexed 1st ray
KNOW THIS
RCSP of varus (compensates just like a rigid FF valgus)
Positional deformity in plantarflexed 1st ray
- AKA flexible plantarflexed 1st ray
- Lesser metatarsal heads are in varus
- Foot type: Mild cavus with vertical calcaneus in RCSP
- Range of motion
Positional plantarflexed 1st ray deformity is acquired due to…
Acquired due to:
o Possible compensation for a supinated foot type (partially compensated and uncompensated forefoot varus and rearfoot varus)
o Achilles tendon lengthening or rupture which leads to overactive peroneus longus in assisting with heel off
o Frank spasm of PL (pulling the 1st metatarsal head down)
Foot type and RCSP seen in positional 1st ray
KNOW THIS
Mild cavus with vertical calcaneus in RCSP*
Rigid and flexible plantarflexed 1st metatarsal
- Shares many of the same signs and symptoms as a rigid forefoot valgus – high arch
- Increased incidence of tibial sesamoid pain and ankle sprains
Dorsiflexed cuboid
- Plane of all the metatarsal heads everted to the rearfoot with STJ neutral and MTJ locked.
- As cuboid dorsiflexes, the 4th and 5th metatarsals are raised above the ground
Dorsiflexed cuboid is acquired due to…
- Acquired deformity due to chronic subluxation of the OMTJ from a tight gastroc-soleus complex.
Dorsiflexed cuboid is compensated for by…
- Compensation for a gastrosoleus or gastroc equinus is by STJ pronation which unlocks the OMTJ to try and keep the heel on the ground by increasing dorsiflexion at the OMTJ.
- This causes a dorsiflexion of the forefoot on the rearfoot
- With the STJ neutral and MTJ locked, the plane of the metatarsal heads will be everted relative to the rearfoot
Foot type seen in dorsiflexed cuboid
KNOW THIS
Foot type is very flat foot
A rigid total forefoot valgus compensates initially by:
o STJ supination
o Supination around the oblique axis of the MTJ
o STJ eversion
o Supination around the long axis of the MTJ
o Dorsiflexion of 1st metatarsal by tibialis anterior
Answer: 4
The RCSP for an isolated flexible FF valgus deformity is:
o Varus
o Valgus
o vertical
Answer: 3
A flexible plantarflexed 1st ray is:
o Associated with lesser metatarsals that are all on the same sagittal plane
o A possible compensation for a FF varus
o A possible compensation for a RF valgus.
o Seen with a weakness of the peroneus longus
2
FOCUS
- Know RCSP (heel) position following compensation
- Know the types of deformities that lead to each compensation and what foot type that leads to
