ankle Flashcards
sensory regions of ankle ? 5 nerves
superficial peroneal: anterior shin and dorsum of foot
deep peroneal: 1st webspace
tibial: medial heel then divides into medial and lateral plantar nerves
saphenous < femoral: medial leg and arch of foot
sural: lateral leg and pinky toe
motor tests for ankle? 4 nerves
- foot eversion: L4/5 superficial peroneal thru peroneus longus/brevis
- dorsiflexion: L4/5 deep peroneal thru TA
large toe extension: L4/5 deep peroneal thru EDL/EHL - plantarflexion/inversion: S1/2 innervation tibial nerve thru TP (inversion), FDL,FHL and calf muscles
special tests to assess pt with ankle injury
wrinkle test; pinch skin to see if viable for OT
syndesmotic squeeze test: squeeze 5cm above joint if pain then possible syndesmotic injury
ankle examination
- ATLS
- inspection: skin condition, blisters, bleeding, open fx
- palpation: soft compartments, pain on passive stretching
- active and passive ROM
- NV exam: 5 sensory, 4 motor
- examine joint above and below
Weber Classification
tibial plafond is marker
infrasyndesmotic is weber A
transyndesmotic is weber B
suprayndesmotic is weber C
Lauge-Hansen Supination-Adduction (Weber A)
based on position on foot and external forces applied
1. 10% of ankle fx
WEBER A/Supination-Adduction
Stage 1: transverse lateral malleolus/ATFL rupture
Conservative (walking boot)
Stage 2: vertical shear of medial malleolus + medial tibial plafond impaction
Lauge Hansen Weber B/Supination-External Rotation
75% of ankle fx
Stage 1: AITFL rupture/Chaput tubercle avulsion
Stage 2: + oblique fibular fx
Stage 3: + PITFL rupture/ PM fx
Stage 4: + oblique MM fx/deltoid rupture
Lauge Hansen Pronation-External Rotation (Weber C)
5% of ankle fx
Stage 1: MM fx / deltoid rupture
Stage 2: + AITFL rupture / Chaput tubercle avulsion
Stage 3: high spiral/oblique fibular fx (Maisonneuve)
Stage 4: PITFL rupture/ PM fx (Dupuytren fx)
Lauge Hansen Pronation-Abduction
10% of ankle fx
Stage 1: MM fx / deltoid rupture
Stage 2: + AITFL rupture / Chaput tubercle avulsion
Stage 3: communited high fibular fx
imaging findings 3 AP, 3 mortise 2 lateral
AP:
- tibiofibular overlap <10mm: syndesmotic injury
- tibiofbiular clear space >5mm: syndesmotic injury
- talar tilt: >2mm diff bw superior and medial joint space
Mortise: allows better view of lateral joint space and lateral process of talus
- tibiofibular overlap <1mm: syndesmotic injury
- medial clear space: >5mm: talar shift
- talocrural angle: line across tibial plafond, second line across tip of both malleoli. 83 degrees
Lateral:
- talar dome should be centered under tibial plafond
- posterior MM fx can be visualised
why can medial ankle joint space only be assessed in neutral foot position
any plantar flexion will increase medial joint space cuz
- talus is broader anterior than posterior so
if foot is plantarflexed (equinus) then the smaller posterior part of talus will show in xray and can make medial space look bigger than normal
how to ensure dead lateral xray of ankle is correct?
to ensure its dead lateral, the medial and lateral borders of joint surfaces should be aligned and form two perfect arcs. more than 2 arcs means its an oblique view
how to assess ankle joint ROM
cradle foot with hand and index holding calcaneus:
dorsiflexion: 15
plantarflexion: 50
how to assess subtalar joint ROM
one hand supporting heel, other hand at subtalar joint creating movement
inversion: 25
eversion: 10
how to assess midfoot ROM
one hand supporting heel, other hand hold forefoot
supination: 20
pronation: 35
nonsurgical indications for ankle fx 3
- isolated MM nondisplaced
- isolated LM with <3mm displacement and NO talar shift
- PM with <2mm displacement and <25% of joint surface
surgical indications of ankle fx 9
o Open fracture
o Fracture-dislocations
o Vascular injury
o Any talar shift
o Isolated medial or lateral malleolus with
displacement not meeting above criteria
o Bimalleolar fractures (both medial and lateral
malleoli)
o Bimalleolar equivalent fractures (lateral
malleolus fracture with medial widening)
o Posterior malleolus fracture with >2mm articular
step-off or >25% of joint surface involved
o Syndesmosis widening/instability
surgical options MM 3
o Lag screw fixation
o Antiglide plate: shear fragment
o Tension band wire: small fragment
surgical options LM 4
o Lag screw fixation + neutralization plate
o Bridge plate
o Intramedullary screw/k-wire placement
o Isolated lag screw fixation
surgical options PM 2
o Antiglide plate
o Lag screw fixation
surgical options syndesmosis
1 or 2 screws; 3 or 4 cortices
