Lisfranc Injury
This is a fracture dislocation of the second metatarsal and midfoot bone (medial cuneiform).
It only accounts for 0.2% of all fractures but is very commonly missed. The injury is usually caused by a rotational and axial loading force in the hyperflexed foot. Clinical symptoms are severe pain, swelling of the midfoot and inability to weight-bear. Radiographs are essential for diagnosis but often a CT scan is required. If there is no displacement on weight-bearing Xrays, treatment with a cast and strict non weight-bearing for 8 weeks is sufficient. Any evidence of instability requires surgical fixation.
5th Metatarsal Base Fracture
Inversion of the hindfoot, adduction of the forefoot or repetitive microtrauma are the main mechanisms of injury.
In zone 1 the peroneus brevis tendon or plantar ligament pulls on the bone and cause an avulsion. Non-healing is uncommon and protected weight-bearing in a stiff soled shoe or boot limited by pain is the main treatment. In zone 2 it involves the joint between the 4th and 5th metatarsal. Nonunion is common (15-30%) and treatment requires at least cast immobilization for 6-8 weeks. Alternatively surgery using a long screw can be utilized. In zone 3 repetitive microtrauma causes stress fractures with poor bone healing. Similar treatment as for zone 2 injuries can be attempted but often sugery and even bone grafting is indicated if the fracture shows signs of sclerosis and obliteration of the medullary canal.