A trimalleolar fracture occurs when the three malleoli bones that make up the ankle break at the same time.
The malleoli are specific parts of the tibia and fibula that form the ankle. These consist of the lateral malleolus, which is at the end of the fibula, the medial malleolus, which is on the inside of the tibia (shinbone), and the posterior malleolus, which is at the back of the tibia.
All three bones are essential for anchoring the ligaments that support movement, control, and stability in the foot and ankle.
As a trimalleolar fracture involves breaks to three bones, doctors consider it more unstable than other fractures, and it may lead to further ligament injury or dislocation.
In this article, we look at how to treat this fracture, how long it takes to recover, and the causes and symptoms of a trimalleolar fracture.
As trimalleolar fractures are often unstable, a doctor will usually recommend surgery as treatment.
Each fracture will require a specific repair procedure during the surgery.
Lateral malleolus fracture
Firstly, the surgeon will realign the bone fragments, returning them to their original position.
The surgeon will then attach screws and metals plates to the outer surface of the bone to hold them in place.
For some people, the surgeon may insert a screw or rod inside the bone to keep the bone fragments together as they heal.
Medial malleolus fracture
Surgery on the medial malleoli can improve the chances of successful healing and allow the person to resume normal movement sooner.
Sometimes, a medial malleolus fracture may result in impaction of the ankle joint, which is when force drives one bone into another. When this occurs, a surgeon may need to do a bone graft, which acts as a frame on which new bone can grow. Bone grafting can reduce the risk of arthritis.
A surgeon can fix bone fragments using screws, plates, and wiring techniques.
Posterior malleolus fracture
There are different options for surgery on this malleolus. One option involves inserting screws that run from the front to the back of the ankle or the other way around.
The other option involves fitting plates and screws along the back of the tibia.
While doctors often recommend surgery after a trimalleolar fracture, surgical intervention might not be appropriate for all people.
People with serious health problems for whom the risk of surgery would be too significant or those who cannot walk will often receive nonsurgical treatment.
Immediate treatment usually involves applying a splint to stabilize the ankle until the swelling reduces. The doctor may then fit a short cast that they replace with smaller casts as the swelling continues to go down.
The person will need regular X-rays to ensure the ankle remains stable.
A person may not be able to put any weight on their ankle for around 6 weeks. After this time, they may be able to wear a removable brace as the ankle continues to heal.
If a person has had surgery, they will be unable to put weight on the ankle for some time.
The amount of time will depend on several factors, including the stability of the bones and how severely the injury affected the surrounding joints.
Often, a person will experience severe swelling around the fracture. This swelling can affect recovery in the following ways:
- delay further surgery
- cause blisters on the skin
- increase the chance of infection
- prolong the healing process.
A physical therapy routine will be vital for a full recovery.
A trimalleolar fracture of the ankle often results from a high-impact injury, such as from a sport or car accident. However, a simple trip or fall can also cause the injury.
A severe sprain can often feel the same as a break, but the following are common symptoms for a fractured ankle:
- immediate and severe pain
- tenderness to the touch
- an inability to put weight on the damaged ankle
The ankle might also appear to be out of place or have a deformity.
An ankle injury needs prompt examination by a doctor. After going through a person’s medical history and symptoms, as well as the events that led to the injury, the doctor will perform a physical examination.
If the doctor suspects a fracture, they will carry out additional tests to gain more information. Tests include:
- X-ray: This is the most common way to diagnose a fracture. An X-ray can show any breaks or displacement in a bone. It can also identify how many pieces of broken bone there are in the area of the break.
- Stress test: This is a special X-ray to check whether surgery is necessary
- A CT scan: This can help a doctor further evaluate the injury. It is particularly useful if the fracture has extended to the ankle joint.
- An MRI scan: This test produces high-resolution images of the anklebones and soft tissue. It can also help a doctor evaluate any damage to the ligaments.
Some complications may develop due to ankle fractures. One complication is malunion, in which the bones move during recovery and are out of place after healing.
Malunion usually only occurs after nonsurgical treatment. It can make the ankle unstable and may eventually lead to arthritis.
Other complications include:
- blood clots in the leg
- damage to blood vessels, tendons, or nerves
- problems with bone healing, such as non-union, in which the bones do not connect after recovery
The three malleolus bones can all undergo separate fractures without affecting the others in the group.
A bimalleolar fracture, which involves breaking two of the three malleoli, can also occur. Most people with bimalleolar fractures break the lateral and medial malleolus.
Some people also experience a bimalleolar equivalent fracture. This occurs when the ligaments on the inside of the ankle incur damage as well as one of the malleoli. In many bimalleolar equivalents, the fibula breaks and injury occurs in the medial ligaments.
Doctors usually recommend surgery for both bimalleolar fractures and bimalleolar equivalent fractures because they can make the ankle unstable and lead to a dislocation.
A trimalleolar fracture is a serious injury that will dramatically reduce a person’s mobility and quality of life while the injury heals.
It is essential that people help with their rehabilitation by undertaking physical therapy and doing home exercises to strengthen the ankle. Even after the fracture has mended, it can still take months for the muscles to regain enough strength so that a person can walk correctly.
With full rehabilitation, a person can regain full mobility following an ankle fracture. However, this may take up to 2 years, according to the American Academy of Orthopaedic Surgeons.