Case Discussion by Eric Malone, MD
Visual Stimulus Case:
A 26 year old male with a past medical history of schizophrenia presents after jumping out of a second story window in a possible suicide attempt. He was brought to the emergency department on petition and was originally taken to the crisis center, where, in addition to intramuscular haloperidol and lorazepam, he also received a foot X-ray, which is provided below.
He has no other injuries and complains only of right foot pain. Examination shows deformity of the dorsal aspect of the right foot with tenderness and soft tissue edema over the midfoot. Range of motion in the right ankle is intact, as are peripheral pulses and neurologic function.
- Based on the above X-ray, which of the following is the most appropriate course of management:
A. Order more haloperidol and lorazepam because the patient is clearly malingering and there is nothing wrong with his foot.
B. Posterior mold right leg splint (with stirrups), non-weight bearing on the right leg, crutches, adequate analgesia and rapid orthopedic outpatient follow up (following completion of psychiatric evaluation)
C. Pain control, preoperative laboratory studies, and emergency department orthopedic consultation
D. Post-op shoe, pain control, PRN orthopedic or podiatric follow up.
- In addition to the findings that you identified on the above x-ray, which of the following other injuries is also likely present:
A. Occult talar dome fracture
B. Disruption of the ligamentous structure of the midfoot at the tarsometatarsal joint
C. Disruption of the vascular supply of the fifth metatarsal head
D. Calcaneal tendon rupture
- Failure to diagnose and appropriately manage this injury pattern is most commonly associated with which of the following:
A. Midfoot instability and collapse, severe arthritis
B. Avascular necrosis of the fifth metatarsal head
C. Atrophic degeneration of musculature of the dorsal foot including extensor digitorum brevis
D. Fracture non-union
The radiographs demonstrate a fracture through the base of the second metatarsal. In addition, there is widening of the joint space between the base of the first and second metatarsals and inferolateral subluxation of the first and second metatarsals relative to their respective cuneiforms. As with seemingly all orthopedic injuries, this pattern has an eponymous description. This injury pattern is known as a Lisfranc injury.
Lisfranc injuries refer more generally to a pattern of injury that involves disruption of the Lisfranc joint. As shown below, the Lisfranc joint is described anatomically as the articulation between the bases of the metatarsals and cuneiform bones.
This joint extends across the midfoot. Any disruption with or without fracture can be described as a Lisfranc injury. Notably, not all such injuries involve obvious metatarsal fractures; some are subtle and involve only ligamentous injury. Note that in the normal anatomical relationships of the midfoot, the proximal metatarsal articulates with the tarsal bones such that the borders of each are aligned, as shown below. The medial border of the second metatarsal aligns with the medial border of the middle cuneiform on the AP view. Presence of an avulsion fragment within the joint space between the first and second metatarsals is known as a Fleck sign (because you can never have enough eponymous ortho descriptors).
Mechanistically, Lisfranc injuries occur as a result of either direct (i.e. blunt) or indirect trauma. With an indirect traumatic injury, the Lisfranc joint undergoes excessive pronation or supination in an already plantar flexed foot, resulting in ligamentous injury. Examination will show midfoot tenderness, soft tissue swelling, potential ecchymosis, and difficulty or inability to bear weight. Plantar ecchymosis is an exam finding specific for Lisfranc injury.
Radiographic evaluation for Lisfranc injuries should focus on the relationships of the midfoot structures described above. In reviewing the x-rays in this case, note the abnormal relationship of the base of the second metatarsal to the cuneiform (red), the widening of the space between the first and second metatarsals (yellow), and the Fleck sign (blue).
Some Lisfranc injuries can be subtle. If history and exam is suggestive of more severe injury than demonstrated by x-ray, weight bearing radiographs or CT should be considered. Failure to diagnose and obtain appropriate early fixation is associated with increased complication rates.
All suspected Lisfranc injuries warrant ermegency department orthopedic consultation, and most will undergo operative fixation and extensive casting as an outpatient. Even when appropriately diagnosed and managed, there is a high degree of post-operative complications, primarily residual pain.
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