Fibular fractures may be isolated or associated with tibia injuries. Isolated fibular fractures are caused by direct lateral leg trauma and are anatomically splinted by an intact tibia. Distal fibular fractures may include a disrupted ankle joint, as evidenced by a widened mortise on the AP radiograph. Tibial fractures are classified by their location, amount of displacement, and presence of comminution.
Compartment syndrome can be seen following a tibia fracture, particularly tibial plateau fractures; distal neurovascular status should be documented. Suspect tibial fractures with trauma to the lower extremity, pain, and inability to bear weight.
The Maisonneuve fracture is a combination of an oblique proximal fibular fracture, disruption of the interosseous membrane and tibiofibular ligament distally, and a medial malleolar fracture or tear of the deltoid ligament. It occurs when an external rotational force is applied to the foot, producing a proximal third fibula fracture. Findings include tenderness at the medial and anterolateral ankle joint in combination with proximal fibular tenderness.
Management and Disposition
Treatment is dictated by the degree of pain and the involvement of the ankle joint. Nondisplaced fractures can be treated with an air cast; those with displacement should receive a sugar-tong splint and referred for short-term orthopedic evaluation. Treatment of a Maisonneuve fracture is most commonly operative.
All open fractures require immediate orthopedic evaluation. Closed fractures that cannot be reduced may also need open reduction. Patients with isolated nondisplaced tibial fractures may be splinted, started on ice therapy, and referred for outpatient treatment. Displaced tibial fractures should also be evaluated by orthopedics due to risk for compartment syndrome.
Early follow-up is required for all tibial fractures due to the risk of compartment syndrome.
The peroneal nerve crosses over the head of the fibula and is subject to injury with a Maisonneuve fracture.
Some patients with Maisonneuve fracture may complain only of ankle pain; always examine the proximal fibula in patients complaining of ankle pain.
Tibial-Fibular Fracture. Deformity associated with a midshaft tibial and fibular fracture. (Photo contributor: Kevin J. Knoop, MD, MS.)
Maisonneuve Fracture. (A and B) Abnormal widening of the medial aspect of the ankle mortise and distal tibiofibular syndesmosis, as well as slight lateral subluxation of the talar dome. Because no “exit” fracture is present on the distal fibula, a fracture of the proximal fibula (C) was suspected and confirmed. (Reproduced with permission of Block J, Jordanov MI, Stack LB, Thurman RJ. The Atlas of Emergency Radiology. New York, NY: McGraw Hill; 2013.)