●For dislocations of the Lisfranc joint line with no apparent tendency to redislocate: non–weight bearing in a short leg cast for 4 to 6 weeks, followed by progression to full weight-bearing in a walker boot
●Further rehabilitation may include sensorimotor training (e.g., the Janda program), training therapy, tailored gait and coordination exercises, and orthotic care
Fig. 4.4 d–f Fractures of the tarsometatarsal joint line (Lisfranc fracture) caused by direct impact trauma. X-ray films taken on site were declared to be negative, but the patient continued to have pain. Only sectional imaging can define the full extent of the injury and direct surgical planning.
d Coronal T1-weighted image shows a bony avulsion with bleeding and tearing of the Lisfranc ligament at the base of the second metatarsal, accom-panied by intracapsular hemorrhage of the Lisfranc joint at the level of the third metatarsal.
e Axial CT shows a multipart fracture of the base of the second metatarsal with bony avulsion of the Lisfranc ligament and a nondisplaced fracture of the third metatarsal base.
f Sagittal CT shows disintegration of the tarsometatarsal articular surface of the second metatarsal.
●Mobilization may be supported by injection or infiltration therapy, chiropractic therapy, osteopathy, and orthovolt therapy
●The patient should not return to sports participation for 4 to 6 months
Operative
Surgical treatment is indicated in patients with > 2 mm of dis-placement and in patients with unstable injuries.
●Complete dislocation: emergency reductions can be done in nonfasted patients (closed technique may be used) and then stabilized surgically with a Kirschner wire, screw arthrodesis, or an external fixation device. Reductions should be centered on the second metatarsal (the “key fragment”), followed by reduction and stabilization of the first metatarsal and then the third through fifth metatarsals.
●Fracture with a subluxated position: Surgical planning is based on CT scans and, if necessary, MRI. Reduction begins with the second ray, then proceeds to the first ray and the lateral rays.
The tarsometatarsal joints can be transfixed with screws or stabilized by dorsal plating. Kirschner wires should be used in patients with critical soft tissues. The only indication for pri-mary arthrodesis is the complete destruction of the first through third tarsometatarsal joints. Transfixation should be in line with the Lisfranc ligament for grade II and III ligament injuries.
●Postoperative care: non–weight bearing in a walker boot for 6 to 8 weeks. A foot that is stable for exercise can be mobilized without weight bearing. Progression to full weight bearing may be started when radiographs confirm fracture healing and transfixation screws have been removed. Screws placed across articular surfaces are removed at 6 to 8 weeks.
Prognosis, Complications
Possible complications:
●Compartment syndrome: requires emergency incision of the four plantar compartments and the dorsal compartment.
Compartmental pressures should be measured, if possible, but decompression incisions should be made, even if doubt exists
●Injury to the dorsal pedal artery
●Persistent or chronic instability, deformity, displacement, posttraumatic osteoarthritis, chronic pain, and loss of foot mechanics
●Rare: avascular necrosis of the cuneiforms, complex regional pain syndrome (CRPS)
4.1.2 Lisfranc Ligament Injury
Definition
A Lisfranc ligament injury is an injury of the ligament that con-nects the medial cuneiform to the second metatarsal.
Symptoms
The clinical picture is highly variable, ranging from nonspecific local pain on pressure and weight bearing to deformity with diastasis between the first and second rays.
●Pain in the first tarsometatarsal joint
●Swelling of the midfoot region
●Inability to bear weight on the affected foot
●Pain on palpation along the tarsometatarsal joints and in res-ponse to a pronation or abduction stress
●It often takes several days for plantar hematoma to appear
●Inability to stand on the toes (always compare both sides)
Predisposing Factors
None.
Anatomy and Pathology
See also 4.1.1 Fractures of the Tarsometatarsal Joint Line (Lis-franc Fractures) (p. 131)
Anatomy
Injury to the Lisfranc ligament is discussed as a separate entity because of its major functional importance. The weak point in the six articulations comprising the Lisfranc joint line is the absence of a direct intermetatarsal connection between the bases of the first and second metatarsals. The first ray is con-nected to the second ray only by the cuneometatarsal ligament (Lisfranc ligament,▶Fig. 4.5). Unlike the four lateral metatar-sals, whose bases are interconnected by stable ligament bands,
Fig. 4.5 Normal MRI appearance of the Lisfranc ligament. Coronal PD-weighted fat-sat image shows a hypointense interosseous ligament running obliquely from the medial cuneiform to the base of the second metatarsal (arrows).
no transverse ligament exists between the first and second metatarsal bases. The strongest ligament within the Lisfranc lig-ament complex is the interosseous liglig-ament; the plantar and dorsal elements are weaker. These anatomic factors account for the high relevance of injuries to the Lisfranc ligament.
Pathology
Mechanism of Injury
A rupture of the Lisfranc ligament leads to significant instabil-ity. The injury is often missed or misinterpreted on initial ex-amination, resulting in significant, persistent complaints. Most injuries occur when the midfoot is twisted while the forefoot is fixed to the ground (e.g., by a cleated shoe). This force causes dorsal displacement of the second metatarsal base with asso-ciated diastasis between the bases of the first and second metatarsals.
Classification
●Classification by the width of the diastasis (can provide a rough guide):
○Stage I: < 2 mm diastasis
○Stage II: > 2 mm diastasis
●Nunley and Vertullo classification (a more precise classifica-tion);▶Table 4.2
Imaging
UltrasoundUltrasound has only a minor role in the routine work-up of these injuries. Increased distance between the medial cunei-form and second metatarsal base, or diastasis increasing to more than 2.5 mm on the weight-bearing radiograph, provide indirect signs of a ruptured Lisfranc ligament. Plantar hemato-ma hemato-may be noted in recent injuries.
Radiographs
●Radiographs of the foot in three planes. Caution: non–weight-bearing radiographs often show no abnormalities!
●Dorsoplantar (DP) and lateral weight-bearing radiographs with side-to-side comparison. The following are indirect signs of a Lisfranc ligament rupture:
○DP: difference in the gap between the base of the first and second cuneiforms is > 2.5 mm
○Lateral: depressed position of the first metatarsal relative to the fifth metatarsal (measured from the plantar cortex of the first metatarsal at the level of the base to the plantar cortex of the fifth metatarsal)
●Alternative stress radiographs: abduction and adduction stress can be applied under fluoroscopic control according to the mechanism of injury (may require anesthesia). Stress radio-graphs can yield more qualitative information than weight-bearing views.
CT
CT is used only to exclude a fracture in cases where MRI find-ings are equivocal and have therapeutic implications.
MRI
Interpretation Checklist
●Continuity of the Lisfranc ligament
●Location of the tear
●Bony avulsion
●Complete fiber disintegration in all portions of the ligament
●Evaluate alignment
●Alignment and congruity of the first and second Lisfranc joints and of the remaining tarsometatarsal articulations
●Exclude associated injuries
Examination Technique
●Standard protocol: Prone position, high-resolution multi-channel coil; contrast administration is not required.
●Sequences:
○Double-oblique coronal PD-weighted fat-sat and T1-weighted images of the midfoot
○Sagittal PD-weighted fat-sat (aligned on the first or second metatarsal)
○Axial PD-weighted fat-sat
○Axial T2-weighted
○Coronal STIR sequence may be added to check for any asso-ciated bone contusions or fractures
MRI Findings (▶Fig. 4.6 and▶Fig. 4.7)
Often the Lisfranc ligament is not completely torn from its at-tachment, and fat-suppressed images show hyperintense bleed-ing in and along the ligament with very poor delineation of in-dividual fiber structures. These findings suggest a sprain of the Lisfranc ligament, which may also cause significant instability.
There may be associated bleeding into the joint capsule and soft tissues as well as focal bone contusion edema or malalignment of the first and second metatarsals.
Imaging Recommendation
The modality of choice is MRI. In recent years MRI has replaced weight-bearing and stress radiographs in clinically suspicious
Table 4.2 Nunley and Vertullo classification of Lisfranc ligament injuries Grade Description
I Sprain of the Lisfranc ligament. Weight-bearing radiographs show no abnormalities. MRI may show signal change in the Lisfranc ligament complex but does not show a discontinuity
II 2–5 mm diastasis on weight-bearing radiographs. Lateral radiographs show no difference between the affected and unaffected foot. MRI may reveal a partial tear of the ligaments
III Extensive disruption of the dorsal and plantar elements with pronounced instability of the first ray; diastasis between the first and second metatarsals; decreased medial arch height on weight-bearing radiograph (plantar cortex of the first metatarsal is lower than that of the fifth metatarsal)
cases with no radiographic abnormalities. MRI is well tolerated even by patients in pain and is sensitive enough to visualize the ligament injury. It can also detect other injuries that may be missed on radiographs.
Differential Diagnosis
●Injury to the calcaneocuboid joint
●Proximal metatarsal fractures
●Cuneiform fractures
Treatment
Conservative●Nunley and Vertullo grade I injuries with less than 2 mm of diastasis can be treated conservatively in a walker boot or non–weight-bearing short leg cast for 4 to 6 weeks.
●Progress to weight bearing supported by an orthotic insert.
●Sports participation may be resumed at 4 to 6 months.
●With chronic instability, consider secondary surgical treat-ment by arthrodesis.
Operative
●Fresh injury of grade II or higher (> 2 mm diastasis): closed re-duction and screw fixation of the ruptured ligament. If other instabilities are also present, additional fixation screws can be placed between the first and second metatarsals and through the first tarsometatarsal joint. The screws are re-moved at 8 weeks, followed by progression to full weight bearing aided by orthotics.
●Chronic instability with intact joints: ligament reconstruction with plantaris longus tendon is an option. Fixation screws are placed for 8 weeks as in a fresh injury.
●Chronic instability with significant degenerative changes in the first tarsometatarsal joint or with an established secondary fixed deformity: arthrodesis of the first tarsometatarsal joint is combined with correction of the deformity.
Fig. 4.6 Rupture of the Lisfranc ligament in a 19-year-old woman with persistent midfoot pain following a stumble. The ligament (arrows) has low signal intensity in the coronal PD-weighted fat-sat image. The interosseous fibers are elongated, edematous, and show continuity disruption. A faint, focal area of bone contusion is visible at its attachment to the distal medial cuneiform. Injury to the capsule and ligaments of the third tarsometatarsal joint is also noted.
Fig. 4.7 a, b Severe Lisfranc joint injury with an extensive rupture of the Lisfranc ligament.
a Coronal STIR sequence shows bone contusions and fracture edema along the Lisfranc joint line with distal avulsion and bleeding of the Lisfranc ligament (arrow).
b Axial PD-weighted fat-sat image shows frac-tures of the medial cuneiform and second meta-tarsal base with advanced traumatic disintegra-tion of the Lisfranc ligament (arrow). Fractures of the third and fourth metatarsal bases are also visible.
Prognosis, Complications
Prognosis! Note
A good outcome requires prompt treatment that is tailored to the stage of the injury.
Most patients can return to their original performance level after appropriate treatment. The prognosis is significantly poor-er if treatment is delayed.
Possible Complications
●Lisfranc fractures are often combined with ligamentous injuries
●Underestimating or missing the injury (sometimes due to spontaneous reduction)
●Compartment syndrome
●Chronic joint instability with chronic pain, painful posttrau-matic (midfoot) osteoarthritis