A midfoot sprain otherwise known as a ligamentous Lisfranc injury is a frequently missed injury in an orthopaedic clinic. These injuries are quite common among sportsmen both amateur and professional. Early and accurate diagnosis is critical in treating these injuries.
The term ‘Lisfranc’ is attributed to the French Napoleonic field surgeon, Jacques Lisfranc. The Lisfranc ligament is the ligament between the medial cuneiform and the second metatarsal. Lisfranc injuries involve the tarsometatarsal joint complex of the foot.These injuries can be purely ligamentous or involve the osseous structures of the foot.The mechanism of injury is usually a direct loading of the joint complex along the dorsal surface.
Historically, Lisfranc injuries are considered to be relatively rare. About 1 per 55,000 yearly, making up for 0.2% of all fractures. However this is likely to be an under-estimation.Up to 20% of Lisfranc injuries are misdiagnosed or missed during the initial radiological evaluation.
Diagnosis of the ligamentous Lisfrancinjury demands a high degree of suspicion. 20% of Lisfranc fracture–dislocations are misdiagnosed or missed during the initial evaluation.Early and accurate diagnosis is a prerequisite for appropriate management in order to avoid long-term sequelae and functional impairment.Presenting features are
- Swelling and pain at dorsal mid-foot
- Bruising on the dorsal and plantar aspect of the foot (Bruising on the plantar aspect is highly suggestive)
- Pain worsens with standing or walking
- Unable to do a “Tip Toe” rise
- Tenderness to palpation along the midfoot.
Weight bearing x-rays are indicated in low-velocity injury,twisting injuries and sports trauma. Comparison with uninjured foot in identical views is important to pick up subtle changes. A MRI scan is not routinely recommended but is useful for cases of non-conclusive radiographs. A CT can be done for preoperative planning rather than for diagnosis.
WHAT TO SEE IN AN X- RAY
- Fleck’ Sign- a bony fragment seen in the space between the first and second metatarsal bases; present in up to 90% of cases
- The most common radiographic finding is diastasis of the base of the first and second metatarsals either alone or with medial and middle cuneiform (> 2 mm)
- However, any fracture of the base of the first three metatarsals is suspicious for a Lisfranc joint injury
Comparison radiograph in a subtle injury– widening of the first and second metatarsals space (circle)
The ligamentous Lisfranc injuries are usually managed conservatively.
Indications for conservative management are
- Less than 2-mm displacement of the tarsometatarsal joint in any plane
- No evidence of joint line instability with weight-bearing or stress radiographs
Modalities of management include
- R.I.C.E therapy (Rest, Ice, Compression, and Elevation) is the mainstay of treatment initially.
- Conservative management in the form of immobilization and non-weight bearing for 6 weeks followed by guarded weight bearing as per tolerance.
In young athletic individuals or in sportsmen who need to go back to sports early we recommend a mini open fixation with a tightrope.This procedure allows us to achieve better reduction across the Lisfranc joint, faster rehabilitation and an earlier return to active sports.