The Maisonneuve fracture is a spiral fracture of the proximal third of the fibula associated with a tear of the distal tibiofibular syndesmosis and the interosseous membrane. There is an associated fracture of the medial malleolus or rupture of the deep deltoid ligament of the ankle. This type of injury can be difficult to detect.
The Maisonneuve fracture is typically a result of excessive, external rotative force being applied to the deltoid and syndesmotic ligaments. Due to this, the Maisonneuve fracture is described as a pronation-external rotation injury according to the Lauge-Hansen classification system. It is also classified as a Type C ankle fracture according to the Danis-Weber classification system.
The Maisonneuve fracture is similar to the Galeazzi fracture in the sense that there is an important ligamentous disruption in association with the fracture. The fracture is named after the surgeon Jules Germain François Maisonneuve.
Cause
Forceful, external rotation of the ankle joint is the main cause of a Maisonneuve fracture. Engaging in high-intensity sports or falling over can increase the risk of tearing the deltoid ligament or cause an avulsion fracture of the medial malleolus from external rotation of the foot.
Signs and symptoms
thumb|282x282px|Fracture of the medial malleolus seen on X-ray scan (left ankle)Common symptoms of a Maisonneuve fracture are pain, swelling, tenderness, and bruising around the ankle joint and inferior (or distal) tibiofibular joint. More specifically, as a pronation-external rotation injury, pain during external rotation of the ankle joint is expected. Additionally, there is a reduced range of motion of the foot and an inability to weight-bear due to ankle pain. Damage to the deltoid ligament or interosseous membrane can cause haemorrhaging around the surrounding tissues, resulting in a localised oedema.
If a Maisonneuve fracture is left untreated, instability of the tibiotalar joint and deltoid ligament can cause a valgus deformity of the ankle. This leaves the ankle joint in a state of chronic pronation, characterised by a protrusion of the medial malleolus into the subcutaneous tissue.
- Forceful, external rotation of the ankle joint results in the tearing of the deep deltoid ligament and/or an avulsion fracture of the medial malleolus.
- The ankle mortise is subjected to excessive torque, rupturing the syndesmotic ligaments and anteromedial ankle joint capsule.
- Rotative energy is transferred upwards along the interosseous membrane, damaging it in the process.
- The force results in a spiral, sometimes an oblique, fracture at the neck of the proximal fibula.
In cases where the anterior aspect of the tibiofibular syndesmosis can resist mechanical stress, only an oblique fracture of the lateral malleolus is produced. Diastasis of the lateral malleolus may also occur, in which it is posterolaterally displaced from the tibia. Stress radiographs of the ankle are used to assess the integrity of the deltoid ligament and tibiofibular syndesmosis.
Based on several clinical results, syndesmotic screws are recommended to be fixed at least 1 centimetre proximal to the tibiofibular syndesmosis or 4 to 6 centimetres proximal to the tibiotalar joint line. Cadaveric analyses, from a comparative study published in Foot & Ankle International in 1997, suggest that screw fixation at 2 centimetres proximal to the tibiotalar joint line is also adequate. Biodegradable implants such as bioabsorbable screws, which do not require postoperative removal, may be used as an alternative to metallic hardware. However, biodegradable implants still limit rotation of the ankle and dorsiflexion of the foot. Immobilisation techniques such as casting are often paired with non-weight bearing precautions.