Chapter 110 - Disorders of the First Ray

Question 1

Define hallux valgus angle

Answer 1

between the long axes of the proximal phalanx and first metatarsal
Normal: <15degrees

** identifies the incongruity at the MTP joint

Question 2

define Intermetatarsal angle

Answer 2

between the long axes of the first metatrsal and the second metatarsal
Normal: <9

** NOT influened by overresection of the medial eminence, not useful for post op eval of distal osteotomies

Question 3

define distal metatarsal articular angle

Answer 3

Angle of line bisecting metatarsal shaft with the line thru the base of the distal articular cartilage cap
Normal: <15

** offset of angle is predisposing factor in developing bunion

Question 4

define proximal phalangeal articular angle

Answer 4

between articular base of the proximal phalanx in relation to longitudinal axis
Normal: <10

Question 5

what radiographic finding is common in juvenile hallux valgus

Answer 5

congruent joint with an increased DMAA

Question 6

in a patient with open physes, how should you correct an increased IMA

Answer 6

medial opening wedge cuneiform osteotomy rather than a proximal osteotomy or fusion

Question 7

in a patient with open physes how should you correct an increased DMAA?

Answer 7

distal biplanar chevron first metatarsal osteotomy

Question 8

associated deformities in hallux varus?

Answer 8

extension deformities of the MTP, IP and a supination deformity of the great toe

Question 9

most common cause of hallux varus?

Answer 9

iatrogenic after hallux valgus correction
1. over resection of the medial eminence
2. excessive tightening of the medial joint capsule
3. overcorrection of the IMA
4. excision of the FIBULAR sesamoid
5. excessive lateral capsular release

Question 10

conditions associated with Hallux Varus

Answer 10

rheumatoid
charcot marie tooth

Question 11

technique for surgical correction of flexible hallux varus?

Answer 11

split EHL transfer with rerouting of the EHB tendon

Question 12

mechanism of injury of turf toe

Answer 12

hyperextension of the MTP with axial load on a plantar flexed foot

Question 13

what posturing suggests severe plantar plate injury

Answer 13

intrinsic minus posturing
- extension of the MTP, flexion of the IP

Question 14

radiographic findings of a plantar plate injury

Answer 14

proximal migration of the sesamoids on the AP radiograph
- indicates complete plantar plate injury

distal sesamoid to joint distance should be no more than 3mm different than the contralateral side

Question 15

chronic plantar plate injury - what surgical options do you have?

Answer 15

abductor hallucis transger

Question 16

what tendon do the sesamoids live in?

Answer 16

flexor hallucis brevis tendon
tibial sesamoid is bipartite in 10% of the population

Question 17

what does fibular sesamoid excision result in?

Answer 17

hallux varus

Question 18

what does tibial sesamoid excision result in?

Answer 18

hallux valgus

Question 19

what does total sesamoidectomy result in?

Answer 19

cock up deformity

Question 20

akin osteotomy

Answer 20

• closing wedge of the proximal phalanx

indications:
- hallux valgus interphalangeus
- congruent deformity

pearls/pitfalls:
- proximal phalangeal articular angle >10
- minimal ability to actually correct the hallux valgus

Question 21

distal soft tissue release

Answer 21

• lateral release with medial exostectomy

indications:
- incongruent deformity
- IMA <11
- HVA <35

pearls/pitfalls:
- avoid fibular sesamoid excision (iatrogenic hallux varus)

Question 22

distal osteotomy (chevron)

Answer 22

• lateral translation of the metatarsal head

indications:
- HVA <30
- IMA <13
- DMAA >15 - use biplanar osteotomy

Pearls/Pitfalls
- avoid lateral release - Increase risk of osteonecrosis

Question 23

proximal metatarsal osteotomy

Answer 23

• metatarsal shaft brought laterally to reduce IMA

indications:
- HVA>35
- IMA >13

pearls/pitfalls:
- overcorrection of IMA can lead to iatrogenic hallux varus
- dorsiflexed osteotomy can lead to transfer metatarsalgia

Question 24

lapidus

Answer 24

• metatarsalcuneiform fusion
  indications:
  hypermobility of the first ray

pearls/pitfalls:
- shortened/dorsiflexed osteotomy can lead to transfer metatarsalgia

Question 25

metatarsophalangeal fusion

Answer 25

indications:
HVA»40
hallux rigidus
RA/inflammatory arthritis
CP/neuro conditions

Pearls/pitfalls: position of fusion: 10degrees valgus, 5 degrees dorsiflexion, and neutral rotation