A Lisfranc injury is a significant injury that involves the midfoot. It is sometimes referred to as a midfoot sprain and it is often has a prolonged recovery time -especially when contrasted with the recovery from an ankle sprain. A Lisfranc injury can involve any combination of fracture, joint dislocation, and/or injury to the stabilizing joint ligaments. The injured area is the junction between the midfoot and the forefoot (tarsometatarsal joint). It is named after the 19th century French surgeon Jaques LisFranc de St. Martin who described the injury. He noted that it commonly occurred when soldiers were knocked off of their horses with their feet caught in the stirrup. Significant disruption of these midfoot ligaments (Figure 1), especially with superimposed fracture of the midfoot bones, typically leads to immediately and often chronic pain, swelling, and 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. This often takes many months. A stable injury to the midfoot, whereby these ligaments are injured (perhaps stretched or partially torn) but not rendered unstable can be treated without surgery. This involves a period (often 6 weeks or more) of non-weight-bearing or limited weight bearing followed by a rehabilitation program to regain full function. A displaced Lisfranc injury usually requires surgery to stabilize the injury followed by an extended period of recovery.
Figure 1A: Lisfranc Joint
Figure 1B: Lisfranc Fracture
Lisfranc injuries typically occur when the midfoot is excessively loaded in abduction, external rotation, and/or dorsiflexion, leading to partial or complete tearing of the strong midfoot ligaments (Figure 1A and 1B). The primary forces also include axial loading (from heel toward toes), and some degree of rotation through the middle joints of the foot. This can occur via a number of mechanisms including:
- A twisting injury such as often occurs in sporting activities (ex. football), where the toes are planted on the ground and the heel is loaded.
- A slip and twist to the foot while descending a step or curb.
- Impact of the foot on the brake pedal, such as occurs in a motor vehicle crash.
Patients with Lisfranc injuries usually have significant swelling and pain in the midfoot, and can often exhibit bruising on the bottom of the midfoot. They find it difficult or impossible to weight-bear due to pain. There is a wide spectrum of Lisfranc-type injuries that can occur, from partial disruption of the ligaments with a stable bony position, to complete disruption of the joints with associated fractures and dislocations. Because the ankle is often uninvolved, the injury may be minimized as just a “foot sprain”, so a high index of suspicion must be maintained to diagnose this injury in a timely manner.
Physical examination reveals specific tenderness to palpation across the midfoot region (Figure 2). There will often be significant swelling of the foot (Figure 3). Patients with Lisfranc injuries will not want to bear weight on the affected foot. In addition, manipulation of the bones of the midfoot will create significant discomfort, specifically twisting the foot downwards and to the outside (pronation and abduction of the forefoot). Bruising in the center plantar aspect (bottom) of the foot is common and should raise suspicion for a significant injury.
Figure 2: Location of Pain
Figure 3: Bruising from Lisfranc Injury
X-rays are taken to identify whether the injury is displaced or non-displaced. Weight-bearing foot x-rays are helpful to determine if the midfoot injury is stable (sprain) or unstable (Lisfranc). Obtaining a comparison film of the other foot is beneficial to see the normal alignment of the person’s foot (which can vary from person to person). A CT scan or MRI may be necessary if the diagnosis or the extent of the injury is unclear. Small bony detail in this region of the foot, as well as subtle fractures and joint displacements, may be more easily identified with advanced imaging. Occasionally, it may be necessary to perform stress x-rays (obtaining an X-ray while twisting the foot) to determine the stability of significant but occult midfoot instability. These tests are important, because they are dynamic assessments of a dynamic problem. CT and MRI scans are more static assessments of these injuries, and can sometimes miss the occult injuries.
There are several classification systems for LisFranc injuries, however the crucial determination is whether or not the injury is stable or unstable.
Stable Lisfranc injuries are usually treated non-operatively. This involves immobilization in either a cast or a prefabricated boot. Patients often need at least a 6-week period where they are either non-weight bearing or minimally weight bearing. In a stable injury, the midfoot ligaments are strained but still intact, so once an adequate amount of healing has occurred, patients can increase their activity level. However, even with a non-displaced injury that is consistent with midfoot sprain, full recovery can still take many months.
Figure 4: Surgical Treatment of Lisfranc Injury
Recovery From Surgery
Recovery from midfoot sprains or overt Lisfranc injuries are lengthy, because the midfoot must absorb tremendous stress during routine stance and gait (weightbearing, stair climbing, walking, running, etc). Post surgical treatment and rehabilitation efforts are thus dependent upon the nature of the initial injury, specific surgical treatment, and the surgeon’s preference. For a major Lisfranc injury, a typical recovery protocol would include:
- 2 to 3 week period of splinted non weightbearing, until swelling and discomfort settle down, and, if surgery was required, sutures can be removed.
- 6- to 8-week period of gradually progressive partial weight bearing in a specialized brace or cast.
- Gradual transition to weight bearing as tolerated in a specialized walking boot for an additional 4-8 weeks.
- Wean from the boot to a stiff sole shoe at 10-14 weeks from surgery, perhaps with subsequent use of a customized semirigid midfoot arch support.
A displaced injury takes many months of recovery. The majority of the recovery occurs in the first 6 months, but it is often a year or more before patients reach their point of maximal improvement.If the surgical treatment fails or the joint damage from the injury leads to severe arthritis, then a fusion (arthrodesis) of the Lisfranc jointsmay be necessary. Despite the stiffness of a fused joint, most patients with successful fusion of the midfoot joints have good function of the foot.