Flashcards in Ankle & Foot Deck (33):
What are the 3 components of the lisfranc joint?
- tarsometatarsal articulation
- intermetatarsal articulation
- intertarsal articular
1st-3rd metatarsals + cuneiforms and 4-5th metatarsals with cuboid
Where is lisfranc's ligament
connects the lateral aspect of the medial cuneiform to the medial aspect of the proximal 2nd metatarsal
What is the mechanism of a lisfranc injury?
dorsiflexion on a plantarflexed foot
rotation about a fixed forefoot
orthobullets: mechanism is usually caused by indirect rotational forces and axial load through hyperplantar flexed forefoot
What are 5 radiographic findings of a Lisfranc injury?
Widening between 1st and 2nd metatarsal
Failure of metatarsal-tarsal alignment (especially second on AP, 3rd on oblique)
Dorsal step off of the MT and tarsals on the lateral
Associated fractures – cuboid, cuneiforms, 1st metatarsal
Fleck sign – avulsion at the base of 2nd metatarsal
What is the normal value for Boehler's angle?
What should align on the AP foot view?
medial aspect of 2nd metatarsal and medial aspect of intermediate cuneiform
What should align on the oblique foot view?
medial aspect of 3rd metatarsal and medial aspect of lateral cuneiform
What are 3 categories of Lisfranc injuries (description of directions)
What are the 2 most common bones fractured in the foot?
Where is Chopart's joint?
Midtarsal joint (between talus and cuboid/navicular)
What is the only bone in the lower extremity without muscle insertion?
What are minor talar fractures?
Chip/avulsion #'s of:
Superior head and neck
Lateral/medial/posterior portions of body
Osteochondral dome fractures
What are major talar fractures?
Talar head 10%
Talar neck 50%
Talar body 25%
What is the incidence of associated injuries with calcaneus fractures (3)?
lower extremity 25%
spine fractures 10%
What is Gissane's angle composed of and what is the normal range?
formed by 2 strong cortical struts - lateral margin of the posterior facet and the anterior beak of the calcaneus
What is the Hawkins classification of Talar fractures?
I: Fracture with displacement but no sublux/dislocation
II: Fracture with subluxation
III: Fracture with dislocation
How do you reduce a talar subluxation/dislocation
Foot in plantarflexion
Longitudinal traction with lateral or medial pressure to achieve reduction
grap by calcaneus
What bones are at risk of AVN?
What is the most common site of talar fractures?
What is the most common mechanism of talar dislocations?
In plantarflexion - posterior aspect of talus is smaller, less area and easier to dislocate anteriorly
Anterior aspect is fatter, wedged
What is the difference between subtalar and total talar dislocation?
Subtalar: talonavicular and talocalcaneus disruption but tibiotalar still intact
Total talar dislocation: tibiotalar disrupted as well
What is a mimic for ankle sprain with prolonged pain?
Osteochondral defect on talar dome
What injury is missed on the Ottawa ankle rule?
Osteochrondral talar dome fracture
*can be picked up on bone scan
What other orthopedic injuries should you consider in calcaneus fractures?
Lower extremity (tib/fib -plateau, femur, pelvis)
Other foot fracture
What is the most common mechanism of injury for calcaneus fractures?
Fall from height, axial load to feet
What are calcaneus fractures at risk for?
Post traumatic arthritis
Soft tissue loss
What is the general management of calcaneus fractures?
Immobilization in dorsiflexion splint vs. boot
Assess for other injuries
What is the mechanism of navicular avulsion fracture? Management?
Non weight bearing boot
What is a nutcracker injury?
Forceful eversion of foot
Cuboid is crushed between calcaneus and forefoot
*cuboids are RARE for isolated injuries
What are cuboid fractures associated with?
Other foot fractures
What are Xray findings of calcaneus stress fractures?
Increased linear opacification (white) perpendicular to the normal lines of the calcaneus
What is the ddx of heel pain?
Plantar fasciitis (worst in morning, with rest)
Plantar fascial rupture
Calcaneus stress fracture
Os trigonum syndrome