Lisfranc (midfoot) injuries: sprains, fractures and dislocations

What is a Lisfranc injury?

The Lisfranc joint complex is where the metatarsal bones (the long bones that run to the toes) meet the tarsal bones (the bones of the arch). A strong ligament holds them together and keeps the arch stable.^[1] A Lisfranc injury can be a sprain (stretched ligaments and an unstable joint), a fracture, or a dislocation in which the bones are forced out of position.^[1] Injuries range from subtle ones, which are now recognized more often because imaging has improved, to severe fracture-dislocations.^[4]

Symptoms

• swelling and pain in the middle of the foot, especially when you press on it or bear weight
• bruising on the top of the foot or the sole (the arch)
• a foot that looks wider than the other side
• in severe injuries, being unable to put weight on the foot^[1,2]

What causes it?

A direct blow, such as a heavy object falling on the foot, can cause it, and so can an indirect force, such as a twist while the foot is planted. Athletes, runners, and people in crashes and falls are among those who injure the midfoot this way.^[1,2] Because it can look like an ankle sprain, the possibility is sometimes overlooked; see ankle pain and swelling and ankle and foot fractures.

How it’s evaluated

We ask how the injury happened and examine the foot for tenderness, swelling and bruising. X-rays are taken, and because a stable-looking foot can hide a ligament injury, standing (weight-bearing) X-rays help show whether the joint is unstable. If suspicion remains and plain X-rays are normal or unclear, a CT scan and sometimes an MRI can be used, and in some cases the foot is examined under anesthesia.^[3,4,1] Early diagnosis matters, because delay is linked to poorer results.^[3,4] X-ray and ultrasound are available on site at our practice, and CT and MRI are arranged with an imaging center; see foot and ankle imaging.

Non-surgical care

A stable injury, with no displacement of the bones on standing X-rays or CT, is generally treated without surgery. Treatment includes a cast or boot without putting weight on the foot for about six weeks, then a gradual return to weight-bearing and physical therapy.^[4,3,1] Anti-inflammatory medicine, ice and elevation help with swelling.^[1]

Not every injury that looks stable stays that way. A systematic review of nonsurgical treatment found widely varying results: some studies reported excellent function, but in one, 54% of patients had late displacement, arthritis developed in 5% to 38%, and up to 56% ended up having surgery. Injuries with no displacement on CT did best.^[5]

When surgery is considered

Some Lisfranc injuries need surgery, and a few need it urgently.^[1] Displaced or unstable injuries are generally treated surgically.^[4] Surgeons haven’t agreed on a single measurement for “unstable”: in a review of 58 studies that gave explicit criteria, the most common cutoff for a gap between the bones was 2 mm or more, but others used 1 mm or 3 mm.^[6]

The two main operations are open reduction and internal fixation (realigning the bones and holding them with screws or plates) and primary arthrodesis (fusing the damaged joints).^[7,8] Which is better remains debated; see Lisfranc surgery for the options, recovery and risks. Swelling after a serious midfoot injury can also build up dangerously in the muscle compartments of the foot, which is a reason to have a severe injury checked promptly.^[1]

When to seek care

Any injury to the midfoot with swelling, bruising on the arch, or trouble standing on the foot should be checked, even if it seems like a sprain.