26: Everted Forefoot Deformities - Mahoney Flashcards Preview

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Flashcards in 26: Everted Forefoot Deformities - Mahoney Deck (18)
1

name three everted forefoot deformities

- forefoot valgus
- rigid plantarflexed 1st ray
- dorsiflexed cuboid

2

All of the metatarsals are on the same everted plane with one being more inferior to five

total forefoot valgus

3

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°)

4

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)

5

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

6

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)

7

foot type flexible FF valgus

severe flatfoot

8

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) ****

9

foot type rigid total forefoot valgus

high-arch, stable cavus

10

structural/rigid plantarflexed 1st ray

- cavus foot
- lesser metheads are on same parallel plane
- 1st ray ROM is more in plantarflexion
- RCSP varus

11

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

12

lesser met heads are in varus
mild cavus foot type
vertical calcaneus in RCSP
ROM less than 10 degrees

positonal/flexible plantarflexed 1st ray

13

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

14

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

15

foot type dorsiflexed cuboid

very flat foot

16

A rigid total forefoot valgus compensates initially by:

Supination around the long axis of the MTJ

17

The RCSP for an isolated flexible FF valgus deformity is:

vertical

18

A flexible plantarflexed 1st ray is:
- assoc w/ lesser met that are all on same sagittal plan
- possible compensation for FF varus
- possible compne for a RF valgus
- seen with weakness peroneus longus

A possible compensation for a FF varus

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