Disclosure Jacques Lisfranc (1790-1847) was a field surgeon in Napoleon's army serving on the Russian front. He wrote about a new amputation technique to treat forefoot gangrene from frostbite. This technique involved a route following a series of joints to avoid having to take the time to cut through bone. This route became known as the Lisfranc joint. However, Lisfranc did not actually describe the injury pattern well known by this eponym. Although the amputation technique survives, the term is used today to describe a wide spectrum of traumatic injuries to this distinct area of the foot. A Lisfranc injury encompasses everything from a sprain to a complete disruption of normal anatomy through these joints. Early recognition and treatment of this injury are important to preserve normal foot function. Problem: The Lisfranc joint line describes the anatomic boundary between the rigid midfoot and the suppler weightbearing forefoot. Instability or disruption of normal support can lead to significant pain and disability for normal ambulation. Frequency: Reported incidence of this uncommon injury is approximately 1 per 55,000 persons per year. Etiology: The 2 major causes of Lisfranc injuries are low-energy loading observed in sports-related injuries and high-energy loading observed in motor vehicle and industrial accidents. In low-energy settings, tarsometatarsal (TMT) injuries are caused by a direct blow to the joint or by axial loading along the metatarsal (MT), either with medially or laterally directed rotational forces. In high-energy injuries, the method of loading is not significantly different, but the energy absorbed by the articulations results in significantly more collateral damage to bony and soft-tissue structures, creating such injuries as MT fractures, cuneiform instabilities, and cuboid fractures. The result is damage to the tight ligamentous structure of this joint complex, which creates an unstable foot for weightbearing. This sense of instability and pain can occur whether or not overt evidence of instability is present. Chronic sprains, which can result from relatively minor trauma, can be the most debilitating sprains due to pain with weightbearing. Clinical: Patients with Lisfranc injuries can present with obvious anatomic deformities or with only variable amounts of pain with weightbearing. Excluding a Lisfranc injury is important in any patient with midfoot pain on either the dorsal or plantar aspect of the foot during weightbearing. Clinical signs include the following:
Schedule all injuries with evidence of nonanatomic alignment for surgery, provided the patient is otherwise a surgical candidate.
Relevant Anatomy: The Lisfranc joint actually is composed of the 5 TMT joints and, as mentioned, serves as the dividing line between the rigid midfoot and the more flexible weightbearing forefoot. These actually are independent joints, differing in size, position, and motion. A transverse line through these joints is not straight but highlights a recess formed by the second TMT joint. This joint lies approximately 1 cm proximal to the first TMT joint line and 0.5 cm proximal to the third TMT joint line. This recess is termed the keystone. The remainder of the joints follow a smooth cascade from medial to lateral. The joints are bound by thick plantar ligaments that form an interlocking pattern between the tarsal and lesser MT bones 2-5. These are reinforced by attachments of the posterior tibialis tendon. The first TMT joint also has strong plantar ligaments across the joint, which are reinforced with the attachment of the peroneus longus and anterior tibialis tendons. Also present between the lesser MTs is a series of intermetatarsal ligaments, which force the group to function more as a unit. No intermetatarsal ligaments exist between the first and second MTs, which is why they often exhibit divergent behavior. The Lisfranc ligament originates from the plantar lateral aspect of the medial cuneiform and attaches to the plantar medial aspect of the second MT base. It is the thickest of the ligaments in this region, measuring up to 1 cm wide. This ligament provides the only soft-tissue link between the medial ray and the lesser MT and is responsible for the area's stability. Motion at the TMT joints also is variable. The second joint is the stiffest, with minimal motion in the dorsal/plantar plane and none in the medial or lateral plane. The third and first TMTs exhibit progressively more motion in both planes but still are relatively stiff and mainly function as areas of adjustment to allow the MT heads to share weight equally. The lateral 2 TMT joints demonstrate roughly 3 times more motion in the dorsal or plantar plane than does the first TMT joint. That motion is significant in the function of the foot and must be preserved to maintain normal function. This joint motion delineation can be simplified further into medial and lateral columns. The medial 3 joints are more important for their rigidity and shock absorption. The lateral joints are more important for their mobile contributions to balance forefoot weightbearing. This principle is important in treating these injuries. Contraindications: Schedule all injuries with evidence of nonanatomic alignment for surgery, provided the patient is otherwise a surgical candidate. Patients with open injuries or vascular compromise should be approached carefully. Anatomic alignment is important for stable function, but the risk of infection and tissue compromise may preclude surgery until the tissues stabilize. A delayed fusion of the medial 3 tarsometatarsal joints can be performed if pain persists with weightbearing. |
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Imaging Studies:
Medical therapy: Medical treatment is reserved for injuries found to be anatomically stable. This type of injury is best labeled a sprain, although associated fractures in the surrounding bone may be present (eg, MT fracture). An athlete with a stable Lisfranc injury usually cannot compete for the remainder of the season. Early return to high-level activity can lead to chronic pain and progressive arthropathy. Initial treatment should consist of a well-molded nonweightbearing short leg cast worn for a minimum of 6 weeks. Advancement of ambulation depends on resolution of symptoms. Because many of these injuries initially present with midfoot edema that may help stabilize damaged tissues, all stable injuries should be reexamined approximately 2 weeks following injury. Obtain weightbearing radiographs to ensure continued anatomic alignment. After 6 weeks, progressive weightbearing can be allowed in a well-molded cast, advancing as comfort allows. When full weightbearing in a cast is comfortable, the patient can be advanced to regular shoe wear and reconditioning. An accommodative orthotic with a well-molded arch can be used as needed for comfort and support. Combined closed reduction and casting has no role in the treatment of unstable injuries. Constantly maintaining reduction with casting alone has proven to be too difficult. Surgical therapy: Schedule all injuries with evidence of nonanatomic alignment for surgery, provided the patient is otherwise a surgical candidate. Complete assessment of the intercuneiform and cuboid integrity is important when determining stability. Clinical outcome is highly dependent on restoration of normal anatomic alignment. Present recommendations for treatment consist of open reduction of the unstable area and rigid fixation with 3.5-mm fixation screws. Multiple Kirschner wires (K-wires) also have been advocated, but maintaining reduction with them is more difficult (see Image 10). Presentation variations
Preoperative details: Supine position with a high-thigh tourniquet is recommended. Be aware of and ready to address all injuries present before beginning surgery. Intraoperative details: A 2-incision approach works best for complete visualization. The medial incision is in line with the first web space. Identify and protect the deep peroneal nerve, dorsalis pedis, and extensor tendons. Once the area of the second TMT joint is reached, perform subperiosteal dissection across the Lisfranc joint to minimize damage to soft-tissue structures. If needed, a second incision is based over the lateral border of the third MT and carried distally. The extensor brevis is divided bluntly, and the TMTs are entered subperiosteally. In this region, the third, fourth, and fifth TMT joints literally are one on top of the other and are visualized easily. With the tarsus stabilized and the joints inspected, reduction usually is easy. The author finds it easiest to reduce the second TMT joint first, but other authors suggest starting with the first. A large pointed bone reduction clamp can be used to hold the reduction while screws are placed. The position of the fixation screws is depicted in Image 14. Because no real tissue layers are present at this level of the foot, wound closure can be accomplished with 2-0 Vicryl to close joint capsules and 3-0 nylon vertical mattress sutures to close the skin. Postoperative details: Rigid immobilization in a nonweightbearing posture still is important for these injuries. Do not allow patients to bear weight for at least 8 weeks; advance only as comfort allows. What period of time that screws should remain and whether weightbearing should be permitted before the screws are removed are still being debated. All agree that screws across viable joints should be left in no longer than 6 months from the time of surgery. Some advocate removal at 3 months postsurgery before weightbearing. The author permits patients to bear weight on these screws for 3 months before removal. Thus, practically speaking, the screws are left in place for 5-6 months postsurgery. Follow-up care:
The following 3 major factors can be considered complications of this injury:
Continued chronic pain along this joint line with weightbearing is best treated with fusion of the first, second, and third TMT joints in an anatomically correct position. With realignment and stabilization of the medial joints, laterally based pain usually subsides. Treat persistent lateral pain following realignment of the medial joints with interposition arthroplasty rather than fusion. This is best performed using a segment of extensor brevis tendon rolled up and stuffed into the debrided joint. This allows continued motion and prevents the compressive bony contact that generates the pain (see Images 19-22).
Anatomic alignment is the best predictor of outcome. The presence of fractures and/or articular destruction leads to poorer results, regardless of alignment.
Role of acute fusion Stability at this joint level of the foot is the primary concern, and instability appears to be the primary pain generator. How to best predict when the ligaments will heal adequately to support the foot is an issue. Because of this issue, some have advocated primary fusion of the medial 3 TMT joints at the time of surgery. Whether or not this improves long-term results is not yet known. Length of time before screw removal Suggestions of length of time that screws should remain in place range from 6 weeks to 3 months after weightbearing begins (up to 6 months from the time of surgery). Results demonstrate that if fixation screws remain in place indefinitely, they have a high tendency to break with time, thereby causing pain. If the joint is not fused purposely during surgery, then some motion is expected; this constant motion causes metal failure. The timing of screw removal is a question. Advocates of early removal stress the fear of early screw failure as the main reason for removal. Others believe that the screws should remain in place even during early weightbearing to slowly help condition the damaged ligaments to resume supporting the foot. Long-term follow-up is needed before this issue can be resolved. Use of different bioabsorbable materials The advantage of using different bioabsorbable materials to provide short-term stability following surgical reduction is that no screws need to be removed. Issues are twofold, as follows:
Studies regarding these questions are ongoing.
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