LISFRANC INJURY / FRACTURE(Midfoot "sprain")

Summary

A Lisfranc (midfoot) injury is a significant injury that often has a prolonged recovery time. Fracture of the midfoot bones and/or disruption of the midfoot ligaments (Figure 1) leads to pain, swelling, and often an inability to weight-bear. During normal standing and walking the ligaments of the midfoot are subject to forces that are 2-3 times body weight. These ligaments and bones must heal before normal walking can occur and this often takes a number of months. A stable Lisfranc injury (midfoot sprain) occurs when some of the midfoot ligaments are torn, but the bones and midfoot joints are undisplaced. Stable Lisfranc injuries are treated with rest, immobilization, and often a period of non-weight-bearing. A displaced Lisfranc injury is associated with significant disruption of the midfoot ligaments (displacement of the tarsometatarsal joint) and is usually treated with surgery to reposition and stabilize the joint(s) followed by prolonged immobilization.

Figure 1A: Lisfranc Joint	Figure 1B:  Lisfranc Fracture

Clinical Presentation

Patients suffering an injury to the midfoot will often disrupt the Lisfranc joint [tarsometatarsal joint] (Figure 1A). Lisfranc injuries occur when the midfoot is excessively loaded leading to partial, or complete disruption of the strong midfoot ligaments (Figure 1B). This can occur via a number of mechanisms including:

• A twisting injury such as often occurs in sporting activities (ex. football) or if the patient slips and twists their foot while they are loading it.
• Jamming the foot on the brake peddle such as occurs in a head on motor vehicle crash.
• Loading through the heel leading to an increased force to the midfoot.
• The injury was originally described by Lisfranc (a Napoleonic era field surgeon) who noticed that horseback riders who were shot, would often fall off their horse, and get their foot caught in the stirrups leading to a disruption of this joint.

Patients with Lisfranc injuries will usually have significant swelling and pain in the midfoot. They will find it difficult or impossible to weight-bear due to pain. There is a wide spectrum of injuries that can occur from partial disruption of the ligaments with a stable bony configuration to complete disruption of the joints with associated fracturing and dislocations.

Physical Examination

Physical examination reveals pain in the midfoot area (Figure 2). There will often be significant swelling of the foot. Patients with Lisfranc injuries will be reticent to bear weight. In addition, manipulation of the bones of the midfoot will create significant discomfort. Bruising in the sole of the foot is common (Figure 3).

Figure 2:  Location of Pain

Figure 3:  Swelling and bruising

Imaging Studies

X-rays are taken to identify whether the injury is displaced or non-displaced. It is often beneficial to obtain a CT scan to assess the extent of the injury or to confirm that the injury is stable. Weight-bearing foot x-rays may be necessary to determine if the Lisfranc injury is stable or unstable. It can be uncomfortable for the patient to stand during weight-bearing x-rays. However, this is only required for the 4-5 seconds of the x-rays are being taken.

Classification

On a basic level, Lisfranc injuries are classified into nondisplaced [stable] and displaced [unstable] injuries. Unstable Lisfranc injuries are characterized by a significant disruption of the strong plantar ligaments. These are the ligaments that hold the arch up. This ends up being more significant injury than even a fracture, as these ligaments take a long time to heal.

Treatment

Stable Lisfranc injuries are treated nonoperatively. This involves relative immobilization in either a cast or a walking boot. Patients often need at least a 6-week period where they are either non-weightbearing or minimally weightbearing through the heel. In a stable injury, some or most of the midfoot ligaments are still intact, so a basic amount of healing is needed and then the patients can increase their activity level. However, even with a non-displaced injury, it is surprising how long the recovery can be!! The patients are still often symptomatic with pain and swelling 8-12 weeks (or even more) after their injury. A non-displaced injury is often thought to be a “foot sprain.” However, unlike an ankle sprain, which recovers relatively quickly, this can take a long time to heal.

Displaced (Unstable) Lisfranc injuries are usually treated surgically -although some surgeons may try and manage minimally displaced Lisfranc injuries non-operatively. Surgery is performed to reduce the joint and stabilize this joint with screws and sometimes a plate (Figure 4). This allows the bones and the ligaments to be stabilized ideally giving the ligaments the opportunity to heal without being repetitively stretched.

Figure 4: Surgical Treatment of Lisfranc Injury

Recovery From Surgery

The post surgical recovery is dictated by the patients injury and the surgeons preference. For a major Lisfranc injury a typical recovery protocol would include:

• 6- to 8-week period of nonweightbearing that is required to allow adequate healing.
• After 6-8 weeks the patients are mobilized weightbearing as tolerated in a walking boot.
• At approximately the 10- to 14week mark, they are transition to a stiff-sole shoe.

A displaced injury takes a number of months to recover. Perhaps, 80% of the recovery occurs in the first 6 months, but it is often a year or more before our patient has reached their point of maximal improvement following a significant Lisfranc injury.

Some patients with major Lisfranc injuries, including significant damage to the articular cartilage of the joints, will benefit from a primary fusion of these joints. In addition, if the joint collapses at a later point, the salvaged procedure would also be a Lisfranc fusion, also known as a midfoot fusion.