Darren McFadden was injured while playing against the Kansas City Chiefs during week seven of the 2011 season. He was initially diagnosed with a “midfoot sprain” and thought to only need a short period of ice and immobilization. McFadden was expected to return to play the Broncos in early November. Unfortunately, this was not the case. It was only last month that McFadden announced that he finally healed from this injury.
Last December it was announced that McFadden had a Lisfranc’s injury. It is not uncommon for these injuries to go undiagnosed because they do not show up on standard X-rays. A simple midfoot sprain can look exactly like a low grade Lisfranc injury.
A Lisfranc injury is a partial or complete tear of the Lisfranc ligament and/or dislocation of the joint with breaks in the bones connecting this joint. In more severe injuries, generally associated with motor vehicle accidents, there are multiple broken bones and significant dislocation of the joint. The diagnosis is very apparent when Lisfranc injuries are severe. Mild to moderate injuries can be more difficult to diagnose because the changes on X-ray are very subtle.
The Lisfranc joint is in the middle of the foot and is defined as the joints that connect the long bones in the foot (the metatarsals) to the bones in the midfoot (the tarsal bones). Multiple ligaments on the top and bottom of these bones hold the joint together. The lisfranc ligament connects the base of the 2nd long bone (2nd metatarsal) to the 1st small midfoot bone (medial cuneiform). The Lisfranc ligament is the strongest ligament in this ligament group. When this ligament is torn, the stability of the entire middle of the foot is compromised.
When a Lisfranc injury is suspected, it’s necessary to X-ray both feet while standing. Since the bases of the metatarsal bones overlap, it is difficult to visualize breaks in the bone in this area. It is also difficult to see subtle displacement of the joint which can occur when the ligament is torn. When standing, the weight of the body will displace the bones normally supported by the Lisfranc ligament. A space between the base of the 2nd metatarsal and 1st cuneiform can indicate a Lisfranc injury. Because there are variations in anatomy, it’s best to X-ray both feet for comparison. Some individuals naturally have a space between these two bones. Physicians with flouroscopy in their office may do stress views. In some cases a CT scan is ordered, but it is generally used when considering a surgical correction.
The mechanism of injury in football is usually a direct force to the foot such as when a player has been tackled from behind while the foot is planted. The force from behind places a tremendous amount of stress through the midfoot, causing complete or partial rupture of the ligament. With a significant amount of force the forefoot may dislocate on the midfoot and there can be breaks in the metatarsal bones.
Early diagnosis is important because untreated injuries can result in chronic midfoot instability and increase the chance of future arthritis. Post-traumatic midfoot arthritis is likely regardless of treatment. The treatment is based on the severity of the injury and may involve a cast and crutches or a walking boot for 6 weeks for minor Lisfranc injuries or surgery with screw placement for more severe Lisfranc injuries.