Lisfranc Fracture Dislocation Flashcards
Lisfranc injuries are relatively uncommon. What is the percentage of occurence of all fx?
0.2% of all fractures
What are the classification systems for describing Lisfranc injuries?
Quenu and kuss
Hardcastle
Myerson
what bone serves as the keystone to the longitudinal arch and Lisfranc joint?
2nd metatarsal
describe the strength of the ligaments of the Lisfranc joint: dorsal/plantar/ interosseous.
interosseous (Lisfranc lig)- is STRONGEST
then the plantar ligaments is next strongest.
the dorsal ones are the weakest- which leads to a greater predominance of dislocations in that direction
Most lisfranc injuries dislocate dorsally. why?
dorsal ligaments are the weakest
how can you stress the TMTJ to see if a fracture-dislocation has occurred?
- while stabilizing the rearfoot, apply an adductory /supinatory force on the lateral aspect around the 5th met base, then an abductory/pronator force near the 1st met base
- each met base is stressed in a dorsal and plantar direction while grabbing the met head. excessive movement dorsally is positive for disruption of the joint.
Describe the Quenu and Kuss classification system.
Homolateral
Isolated
Divergent
Describe the Hardcastle classification system.
Type A: total incongruity dorsally/laterally Type B1: medial dislocation B2: lateral dsilocation Typce C1: partial displacement C2: total displacement
what other imaging should you order besides xray if the dislocation is not obvious?
CT scan
What else should you have an index for suspicion for with a traumatic Lisfranc injury?
compartment syndrome- check neurovascular status
If you decide to do primary arthrodesis as treatment for a LIsfranc injury, what should you fuse?
only mets 1-3
NEVER mets 4-5 because we need the motion here
What radiographic sign is associated with and pathognomonic for Lisfranc injuries?
fleck sign
what is the fleck sign?
subtle cortical avulsion fx from either attachment of the lisfranc ligament in the 1st IM space
