Bimalleolar and Trimalleolar Fractures
Two of the more complex fractures of the ankle are the bimalleolar and trimalleolar ankle fractures. These fractures tend to be very unstable and often require open reduction with internal fixation in order for the fractures to heal.
Table of Contents
- What are Bimalleolar and Trimalleolar Ankle Fractures?
- What are the Symptoms of These Types of Fractures?
- Causes of Bimalleolar and Trimalleolar Fractures
- What are the Risk Factors?
- Diagnosis of Bimalleolar or Trimalleolar Fractures
- Treatment of Bimalleolar and Trimalleolar Fractures
- Complications of These Types of Fractures
- Surgical Risks
Bimalleolar and trimalleolar fractures are complex fractures of the ankle. The ankle actually consists of two malleoli. These are formed by the distal end of the fibula in the ankle and the distal aspect of the tibia in the ankle. The tibia has a posterior portion that can fracture along with a more anterior portion of the ankle. It is termed the posterior malleolus and when it is fractured along with the two main malleoli, it is called a trimalleolar fracture.
The bimalleolar fracture is more common in women and in people who have other medical illnesses. The trimalleolar fracture is more common in those situations in which there has been a great force on the ankle, such as occurs in a motor vehicle accident or skiing accident.
It has been shown that the more bones broken in the ankle, the less stable the fracture is. Ligaments can be torn or damaged as well, leaving the ankle more unstable than ever before.
Because of the currently aging population, there has been an increase in the numbers of bimalleolar and trimalleolar fractures, especially in active but aging people.
The symptoms of bimalleolar and trimalleolar fractures are about the same. Common symptoms seen in these fractures include:
- Extreme pain in the area of the medial and lateral malleoli
- Tenderness to palpation of the medial and lateral malleoli
- Swelling around the entire ankle
- Bruising of the medial and lateral malleoli
- Inability to bear weight on the ground
- Limited range of motion of the affected ankle
- Hearing a crack when the injury happened
- Feeling a crunching in the ankle with attempts to move it
It takes a great deal of force to get these kinds of fractures. They are common in front-end collisions where the foot is pushed into the foot rest or pedals. Motorcyclists can get bimalleolar or trimalleolar fracture by falling off their vehicle and by having the foot pushed into the ground as a result of an accident.
People who fall from a great height can crush their feet and can sustain a bimalleolar or trimalleolar fracture. The greater the height, the better is the chance of the fall resulting in a complex ankle fracture.
Even a misstep down stairs or on uneven pavement can result in a fracture that involves both malleoli and the posterior portion of the tibia. The heavier a person is, the greater is the risk that a misstep can result in a serious injury. Those with osteoporosis have a greater risk of fracturing their ankle in a serious way.
Risk factors for bimalleolar and trimalleolar ankle fractures include:
- Older age
- Sports like skiing or skateboarding
- Being without a seatbelt
- People who work at high heights
- Walking on icy sidewalks or streets
These types of fractures can usually be picked up on using plain film x-ray, especially if the fractures are displaced. Displacement alone can verify that these are unstable fractures in which ligaments have been stretched or torn.
In some cases, the doctor needs to check for instability by putting the patient under general anesthesia and stressing aspects of the joint using fluoroscopy. If, for example, the syndesmosis has been ruptured between the tibia and fibula, it will show up by stressing the ankle in certain ways. These kinds of things need repairing in order to have a stable ankle.
In less common circumstances, the doctor may order a CT scan of the ankle to look for nondisplaced fractures and cracks in the bones that don’t show up on x-ray. The CT scan will reveal cross-sectional images of bones in the lower leg, ankle and foot.
These fractures are unstable by nature and need to be repaired using open reduction and internal fixation in the operation room. The only difference between the two fractures is the need for fixation of the “posterior malleolus” or the posterior aspect of the tibial joint. It is only necessary to be fixed if the piece that has fractured off encompasses twenty percent or more of the joint surface. If it is less than twenty percent, it is treated as an avulsion and left as is.
If the lateral malleolus needs surgery, an incision is made along the side of the distal fibula and bone fragments are replaced into the proper position. When this occurs, metal plates and screws are used to fix the bony fragments together along the lateral surface of the fibula. Sometimes, rods are placed up into the bone itself.
The medial malleolus can yield an unstable fracture. Surgery is done in order to prevent malunion or nonunion of the fracture. Repairing a medial malleolar fracture can involve plates and screws or can involve bone grafting, especially if the fracture is impacted. Bone grafting can shorten the length of time it takes the fracture to heal.
Sometimes special wiring techniques are used to keep the fracture stable while the bones heal.
If the posterior malleolus is not healed properly, it can lead to arthritis of the ankle. The joint surface will not heal properly and the cartilage will be rough. Screws are placed from the back of the ankle toward the front, or vice versa, to hold the posterior malleolus in place.
In bimalleolar fractures, nonsurgical options are rarely acceptable because of the instability of the fracture. It is treated the same way separate lateral malleolar and medial malleolar fractures are treated. There will be a medial and a lateral ankle scar.
Complications of bimalleolar and trimalleolar fractures are greater for those people who are diabetic, smoke, or are elderly. Problems include wound healing delay and a delay in the healing of the bones.
With nonsurgical treatment, there is always the danger that the fracture ends will move out of place and heal in the wrong position. This is called malunion. If a malunion happens or if the ankle becomes unstable after it heals, it can lead to arthritis in the affected joint.
- Increased pain
- Blood clots in the legs or lungs
- Damage to blood vessels, nerves or tendons
- Problems with bone healing
- Arthritis in the ankle
- Pain from the plates, screws and other hardware.
If you or a loved one has suffered an ankle fracture as a result of someone else's negligence and would like to discuss your legal options with an experienced Sacramento Personal Injury Attorney, contact us online or call us at 916.921.6400 to set up a FREE consultation.