26: Everted Forefoot Deformities - Mahoney Flashcards
name three everted forefoot deformities
- forefoot valgus
- rigid plantarflexed 1st ray
- dorsiflexed cuboid
All of the metatarsals are on the same everted plane with one being more inferior to five
total forefoot valgus
2 forms of compensation for forefoot valgus
Inversion of the lateral column of the forefoot must occur to allow the forefoot to purchase the ground during midstance and propulsion
Flexible(total)forefoot valgus (7°)
compensation for a forefoot valgus follows acronym LASSO
LAS is MTJ longitudinal axis supination-this occurs with the flexible FF valgus
S is STJ supination and O is MTJ oblique axis supination-these occur with rigid FF valgus (after first undergoing LAS)
why does flexible/total forefoot valgus lead to sever MTJ instability during propulsion?
Leads to severe MTJ instability during propulsion even though the heel is vertical in RCSP ***flatfoot
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
In flexible FF valgus, the heel remains vertical (the STJ does not need to compensate for the deformity), but the medial arch drops
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)
foot type flexible FF valgus
severe flatfoot
describe 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.
- Heel is in varus in RCSP *** (know this for all) **
foot type rigid total forefoot valgus
high-arch, stable cavus
structural/rigid plantarflexed 1st ray
- cavus foot
- lesser metheads are on same parallel plane
- 1st ray ROM is more in plantarflexion
- RCSP varus
how would you acquire positional/flexible plantarflexed 1st ray?
- possible compensation for a supinated foot type (partially compensated and uncompensated forefoot varus and rearfoot varus)
- Achilles tendon lengthening or rupture which leads to overactive peroneus longus in assisting with heel off.
- Frank spasm of PL
lesser met heads are in varus
mild cavus foot type
vertical calcaneus in RCSP
ROM less than 10 degrees
positonal/flexible plantarflexed 1st ray
what happens as cuboid dorsiflexes?
As cuboid dorsiflexes, the 4th and 5th metatarsals are raised above the ground
Plane of all the metatarsal heads everted to the rearfoot with STJ neutral and MTJ locked = everted foot type
With the STJ neutral and MTJ locked, the plane of the metatarsal heads will be everted relative to the rearfoot
how do you acquire dorsiflexed cuboid?
Acquired deformity due to chronic subluxation of the OMTJ from a tight gastroc-soleus complex
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
foot type dorsiflexed cuboid
very flat foot
