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LISFRANC INJURY OF THE FOOT

The Lisfranc injury to the forefoot is thought to have originated with Napoleon’s surgeon named Jaques Lisfranc (1790 – 1847) who whilst serving on the Russian front, described a new amputation technique to treat forefoot gangrene from frost bite, which developed after riders fell from their horses with their foot caught in the stirrup. (Englanoff et al., 1995, Vuori and Are, 1993). This technique involved following a series of joints in order to avoid having to take the time to cut through bone.

A Lisfranc injury encompasses everything from a sprain to a complete disruption of the normal anatomy of the joints of the forefoot. (Hesp et al., 1984)

With the Lisfranc joint line describing the anatomic boundary between the rigid mid foot and the more mobile forefoot (Burroughs et al., 1998) .

Injuries to the tarso-metatarsal joint (also known as Lisfranc injuries) are uncommon and can be difficult to diagnose. (Ref. Harwood and Raikin, 2003). The report incidence of Lisfranc joint fracture dislocations is approximately 1 per 55,000 person per year. (Mantar and Burtis, 1994 Englanoff et al., 1995). They are commonly misdiagnosed during the initial examination, with as many as 20 percent of Lisfranc joint injuries being missed on the initial antero-posterior and oblique radiographs (Englanoff et al, 1995; Trevine and Kodros, 1995; Burroughs et al., 1998; Perron et al 2001 .

In a retrospective review of x-rays of 750 patients treated for tarso-metatarsal joint injuries or metatarsal fractures (Vuori and Are, 1993) found Lisfranc joint injuries in 9% (66) of patients. Nineteen percent (12) patients had a total dislocation, 71 percent (47) had a partial dislocation, and 11% (7) a substantial injury of the Lisfranc joint. Although they are classically described in the trauma literature (Burroughs et al., 1998) , they have rarely been described as a result of sports participation, and there was no apparent relationship between the mechanism of injury and the type of Lisfranc joint dislocation.

Due to the fact that 20% of tarso-metatarsal fracture – dislocations are overlooked, in the presence of suggestive clinical findings and negative routine x-rays, stress films in eversion-pronation and inversion-supination should be obtained under general anaesthetic (Goossons and De Stoop, 1983).

* Anatomy
The Lisfranc joint is composed of the articulations between the five tarso-metatarsal joints (Hesp et al., 1984; Mantas and Burks, 1994), although Myerson (1989) suggests that to avoid confusion, the term “Lisfranc joint complex” should be used to refer to tarso-metatarsal articulations and the term “Lisfranc joint” should be applied to the medial articulation involving the first and second metatarsals with the medial and middle cuneiforms.

Transverse ligaments join the bases of all the metatarsals with the exception of the articulation between the first and second metatarsals (Hesp et al., 1984; Mantas and Burks, 1994).

The Lisfranc ligament spans the medial cuneiform and the base of the second metatarsal, originating from the lateral plantar aspect of the medial cuneiform. It is the thickest of the ligaments in the region providing the only soft-tissue link between the medial ray and metatarsals, affording the area its stability ( Shapiro et al., 1994). The joint capsule and dorsal ligaments provide only minimal support on the dorsal aspect of the Lisfranc joint (Wiley, 1971; Heckman, 1991; Mantas and Burke, 1994)

A transverse line through the tars-metatarsal joints is not straight but highlights a recess formed by the second metatarsal, which lies within a mortise created by the three surrounding cuneiform bones (Englanoff et al., 1995). The osseous architecture of the joint, with its “keystone” wedging of the second metatarsal into the cuneiform, confers stability to the joint in the absence of ligamentous connections between the first and second metatarsal heads (Englanoff et al., 1995).

The joints are bound by thick plantar ligaments arranged in an interlocking pattern between the tarsal and second to fifth metatarsals, and are reinforced by attachments from the tibialis posterior tendon (Shapiro et al., 1994).

Due to this anatomical configuration, the second metatarsal is prone to dorsal dislocation when an axial load is applied, when the foot is positioned in extreme plantar flexion.

Anatomy Clinical Presentation
Midfoot swelling and the inability of the patient to weightbear on the affected foot, either immediately after the injury or when examined at a later date ( Burroughs et al., 1980). Palpation, with pain, along the tarso-metatarsal joints
Indicates a midfoot sprain. (Trevino and Kodros, 1995). In addition, stress should be applied to the tarso-metatarsal joints with passive pronatory and supinatory movements (Harwood and Rakin, 2003).

Pain can localize to the medial or lateral aspect of the foot in the tarso-metatarsal region with digital palpation, or it can be produced by abduction and pronation of the forefoot whilst the hindfoot is fixed; which may be the only movement which reproduces discomfort in subtle injuries (Ref. Trevino and Kordos, 1995).

X-ray analysis should include weight-bearing antero-posterior, lateral, and oblique radiographs of the foot as non-weightbearing views of the foot can be normal (Mantas and Burks, 1994; Burroughs et al., 1998) . In addition, even if the first set of x-rays are normal, as the swelling decreases with time, this may allow the bones to move from their normal position, especially if the stabilizing ligaments have been torn. For this reason, it is often necessary to take x-rays during the healing process and evaluate for the possibility of delayed development of instability (Myession, 1989).

On x-rays, tarso-metatarsal dislocation is indicated by
(i)&nbsp &nbsp &nbsp &nbsp loss of the in-line arrangement of the lateral margin of the base of the first metatarsal with the lateral edge of the medial cuneiform.
(ii)&nbsp &nbsp &nbsp &nbsp Loss of the in-line arrangement of the medial boundary of the base of the second metatarsal with the medial boundary of the middle cuneiform. (Buzzard and Briggs, 1998) .

The lateral foot x-ray may indicate a “step-off”, suggesting that the dorsal surface of the proximal second metatarsal is higher than the dorsal surface of the middle cuneiform (Markowitz et al., 1989).

Differential Diagnosis and Associated Injuries longitudinal stress injuries

Cuboid fracture
Navicular Compression fracture
Ruptured tibialis posterior tendon
Comportment syndrome


Treatment
Early diagnosis of a Lisfranc joint injury is imperative for proper management and the prevention of a poor functional outcome (Mantas and Burks, 1994). Even when the diagnosis is established, the optimum treatment approach and prognosis are subject to controversy (Harwood and Rakin, 2003).

If clinical evaluation indicates a mild sprain (pain at the joint, with minimal swelling and no instability) or moderate sprain (increased pain and swelling at the joint,) According to Brown and Gumbs, (1991), treatment by immobilization in a short-leg walking cast (Heckman, 1991) or removable short-leg orthotic or non-weightbearing cast (Trevino and Kodros, 1995) is advocated for four to six weeks, or until symptoms have resolved.

Most investigators, though (Hesp et al., 1984; Heckman, 1991; Mantas and Burks, 1994; Buzzard and Briggs, 1998 have concluded that with fracture dislocations of greater than 2mm, there is little place for non-operative management, as it is difficult to maintain anatomic reduction by closed reduction and immobilization alone.

Immobilization in non weight bearing is usually recommended for at least eight weeks (and possibly up to twelve weeks) with the timing of screw removal being debatable (Myerson et al., 1986). Suggestions range from six weeks to six months from the time of surgery (Mantas and Burks, 1994; Trevino and Kodros, 1995; Myerson 1989), and some authors (Arntz & Hansen, 1987) recommend the patient continues to wear a protective shoe, with a well moulded orthotic for three months after cast removal.

Conclusion
Injuries to the tarso-metatarsal joint are uncommon, but it is important to be aware of these injuries when assessing patients with acute foot trauma.