Lesser MPJ and Digits

Question 1

What is the MPJ axis

Answer 1

vertical-passive transverse motion

Transverse-active sagittal plane motion

Question 2

What is the MPJ fxn in gait

Answer 2

Dorsiflexion required during propulsion

Question 3

What is toe stabilization against the ground during propulsion of the MPJ done by?

Answer 3

FDB and FDL and assisted by the weaker interossei and lumbricals

Question 4

How is dorsiflexion of the MPJ done?

Answer 4

by EDL through extensor sling

Question 5

Primary metatarsalgia

Answer 5

intrinsic forefoot abnormalities related to metatarsal anatomy-overload of adjacent mets causing pain

Question 6

Seconday metatarsalgia

Answer 6

Extrinsic pathology that indirectly overloads second to fourth metaheads

Question 7

What causes secondary metatarsalgia?

Answer 7

hallux rigidus, MPJ instaility, neuropathic pain, neuroma or tarsal tunnel

Question 8

Iatrogenic metatarsalgia

Answer 8

caused by malunion after met osteotomy, shortening of 2nd met d/t nonunion or fx deformity

Question 9

Intrinsic cause of predislocation syndrome

Answer 9

RA

Question 10

Extrensic causes of predislocation syndrome

Answer 10

long or plantarflexed 2nd met, long 2nd digit, short 1st ray, 1st ray hypermobility, HAV, dorsiflexed 1st ray, pronation, equinus

Question 11

What is the relationship between equinus and metatarsalgia?

Answer 11

foot compensate for decreased ankle DF by increased use of EDL and EHL during swing phase. THis shifts weight bearing pressure from hindfoot to forefoot. Also, overextension of MPJ uncovers metheads giving more force to them

Question 12

Clinical findings of metatarsalgia/predislocation syndrome

Answer 12

pain 2nd mpj, may have edema, 2nd digit doesnt purchase ground, negative moulder’s click(no neuroma), adducted toe abutting hallux, pn with 2nd MPJ motion

Question 13

Stage 1 of predislocation syndrome

Answer 13

mild edema dorsal and plantar to lesser MPJ, tenderness plantar and distal to the joint, alignment of digit unchanged

Question 14

Stage 2 of predislocation syndrome

Answer 14

moderate edema, noticeable deviation of digit both clinically and radiographically, loss of toe purchase seen in WB

Question 15

Stage 3 of predislocation syndrome

Answer 15

moderate edema, deviation is more pronounced, subluxation or dislocation radiographically

Question 16

How is dorsiflexion at the lesser MPJs done?

Answer 16

EDL through the sling which supports proximal aspect of prox phalanx

Question 17

How is dorsiflexion of middle and distal phalanges done?

Answer 17

through extensor wing controlled by lumbricals

Question 18

What causes hammertoes?

Answer 18

imbalance of extrinsics and intrinsics, the IO neutralize or limit dorsiflexory forces at MPJ in gait, they neutralize FDL and FDB passive buckling, lumbricals create plantarflexion of MPJ, DF of PIPJ and DIPJ

Question 19

3 etiologies of hammertoes

Answer 19

flexor stabilization, flexor substitution, extensor substitution

Question 20

Flexor stabilization-hammertoes

Answer 20

pronation-flexors fire earlier and stay contracted longer to stabilize-most common

Question 21

flexor substitution-hammertoes

Answer 21

occurs in supinated foot, flexors gain advantage over IO-PL pull leads to PF 1st ray which creates weightbearing supination-least common

Question 22

Extensor substitution-hammertoes

Answer 22

swing phase excessive digital contracture, EDL gains advantage over Lumbricals, pes cavus, equinus, decrease/resolves w/ WB initially

Question 23

Adductovarus etiology

Answer 23

loss of mechanical pull of QP leads to medial pull of FDL-results in adductovarus pull of 5th toe

Question 24

Radiograph findings of tailor’s bunion

Answer 24

intermetatarsal angle: nl 6.5 degrees-abnl 8.7

lateral deviation angle: nl 2.6, abnl 8

Question 25

Type 1 tailor bunion

Answer 25

enlargement of lateral surface of 5th met

Question 26

Type 2 tailor bunion

Answer 26

secondary to abnl lateral bowing with a nl 4-5 IM angle

Question 27

Type 3 tailor bonion

Answer 27

increased IM angle between 4th and 5th mets

Question 28

Type 5 tailor bunion

Answer 28

combo of deformities-most common with RA