McG 19: Plantar Plate

Question 1

cause of plantar plate dysfunction

Answer 1

1st ray insufficiency causes lateral weight transfer to the 2nd MTPJ

Question 2

why are 2nd MTPJ crossover most common

Answer 2

2nd MT is locked int he mortise of the Lisfranc jt, it becomes the pivot point of the FF during propulsion

Question 3

what happens at the 2nd MT-cuneiform jt when HAV is present

Answer 3

proximal transfer to the 2nd MT-cuneiform jt resulting in degenerative arthritis

Question 4

how do hammertoes develop

Answer 4

progressive 2nd HT deformity that parallels the degree of the HAV, beginning w/ a sagittal contracture at the PIPJ and MTPJ, then medial and various drift and subluxation of the MTPJ and finally dorsal dislocation of the MTPJ

Question 5

symptoms of pre dislocation syndrome

Answer 5

> pain to plantar sulcus (NOT plantar to MT head)

>dorsal effusion around 2nd MTPJ (occludes visualization of extensor tendon)

Question 6

what is the most common sign of a ruptured plantar plate

Answer 6

• dorsally contracted 2nd toe at the MTPJ w/ or w/o digital contractors when WB
• unable to purchase the ground

Question 7

ddx for floating toe

Answer 7

• prior sx w/ dorsal contracture

- bradymetatarsia

Question 8

name 2 clinical test to diagnose plantar plate injury

Answer 8

• Kelikian push-up test

- Lachman Drawer test

Question 9

conservative tx options for plantar plate injury

Answer 9

• plantar sling taping
• off-WB (avoidance of narrow or high heeled shoes)
• activity modification (cross-training, avoidance of toe raise, or sprinting type exercises)

Question 10

plantar plate tear can be misdiagnosed as what

Answer 10

• neuroma
• distal MT stress fx
• Frieberg dx/osteonecrosis
• Systemic autoimmune arthritis (RA, Psoriasis)
• Gouty or infectious arthritis

Question 11

medial drift of the 2nd toe is indicative of what

Answer 11

plantar lateral weakness or rupture of the plantar plate (NOT splaying 2/2 to a neuroma

Question 12

DP radiograph assesses

Answer 12

• transverse alignment of the toe to the MT

- rectus, adducted, abducted

Question 13

Lateral radiograph assesses

Answer 13

• sagittal angle of the proximal phalanx to the ground

- congruous, subluxed or dislocated

Question 14

oblique radiograph assesses

Answer 14

• accentuates the resting position of the 2nd toe to the MT

- assesses for arthritic changes

Question 15

What will you see on MRI

Answer 15

• joint effusion
• thickening of plantar plate
• rupture

Question 16

what is the normal thickness of the plantar plate

Answer 16

2-3mm

Question 17

what is the thickness of an inflamed plantar plate

Answer 17

4-6mm