- See:
Lisfranc's Frx:
- Anatomy of the Midfoot:
- Radiographs:
- w/ questionable injury, consider wt bearing AP view to assess 1-2 interval;
- if standing AP is unacceptable to the patient then consider CT scan;
-
abudction stress AP:
- in the study by HS Coss MD et al 1998, cadavers had ligamentous sectioning and then underwent abduction stress AP x-rays;
- motivation for the study is the observation that w/ Lisfranc strain, abduction stress will move the forefoot laterally;
- in a control population a line tangential to the navicular and medial cuneiform (medial column line) intersected
the base of the first metatarsal (even with abduction stress);
- in cadavers w/ ligamentous sectioning and applied abduction stress, the medial column line falls medial to the metatarsal;
- the authors also noted that the abduction stress AP needs to be taken w/o pronation or supination;
- of note, these authors noted that cadavers w/ ligamentous sectioning, did not show more than 1.5 mm of widening w/ simulated wt bearing;
- Lisfranc Sprains:
- true severe sprains of the Lisfranc joint are somewhat uncommon because the base of the second
metatarsal is recessed between the medial and lateral cuneiforms, and therefore it is difficult
to dislocate the Lisfranch joint without sustaining a frx at the base of the second metatarsal;
- note that when true Lisfranc sprains occur (with disruption of Lisfranc's ligament), the injury will most
often be due to high energy trauma (MVA) rather than from sporting events;
- when sprains of this joint complex, they must be adequately protected & immobilized until soft tissue healing is complete;
- cosider 6 weeks in a non wt bearing SLC to ensure complete healing;
- on a weight bearing AP, any diastasis at the 2nd metatarsal - medial cuneiform articulation, warrents closed
reduction and
percutaneous scew fixation;
- Minimally Displaced Lisfranc Fractures:
- closed reduction and casting may be indicated for fractures that initially present minimally displaced (less than 2 mm
of displacement (compared to opposite uninjured foot) and less than than 15 deg of talometatarsal angulation);
- some orthopaedist demand an anatomic reduction for younger patients;
- it was noted by Potter et al. 1998, that when there was more than a 2 mm inter-metatarsal separation (compared
to the opposite side), then there was often a complete tear of the Lisfranc ligament;
- these author's criteria for surgery was a complete tear of the Lisfranc ligament;
- other orthopaedists note that using 2 mm as a criteria for surgery is arbitrary and is based on a paucity of evidence;
- w/ displaced fractures, closed reduction & casting is unlikely to provide good results;
- as swelling subsides, gains of reasonable reduction will be lost & subluxation will recur;
- therefore internal fixation w/ pins or screws is recommended;
Subtle injuries of the Lisfranc joint
Midfoot sprains in collegiate football players.
SA Meyer et al.
Am J. Sports Med. Vol 22. 1994. p 392-401.
Magnetic resonance imaging of the Lisfranc ligament of the foot.
HG Potter MD et al.
Foot and Ankle International. Vol 19. No 7. July 1998. p 438.
Abduction stress and AP weightbearing radiography of purely ligamentous injury in the tarsometatarsal joint.
HS Coss et al. Foot and Ankle Internationa. Vol 19. No 8. Aug 1998. p 538.
