Traumatic Ankle Fractures and Fracture/Subluxations
The ankle is part of the body that is very prone to fractures, especially with falls, sports injuries, and motor vehicle accidents. There are three bones that make up the ankle joint and a fracture can involve any of these three bones. They include the tibia, the fibula and the talus. The tibia is also referred to as the “shin bone” and is the major supporting bone of the leg at the level of the ankle. In an ankle fracture, it is the distal (far end) part of the tibia that is fractured. The fibula is the outer lower leg bone and is the most common ankle bone to be fractured. Like the tibia, it is the distal end of the bone that is involved in the fracture. The talus makes up the foot part of the ankle and is less commonly fractured than are the tibia and fibula.
The distal ends of the tibia and fibula form prominences on either side of the ankle. The distal end of the fibula is called the lateral malleolus and the distal end of the tibia is called the medial malleolus. If the rear aspect of the tibia is involved, this is called a posterior malleolar fracture. In some cases, the two parts of the tibia and the fibula can be fractured, yielding what is called a tri-malleolar fracture.
Ankle fractures can be relatively minor and can involve just an avulsion of bone from the distal fibula. These are often treated as severe sprains with good results. More severe ankle fractures may require surgery because part of the fracture has become unstable and has dislocated from its normal position. Ankle fractures can be associated with ligamentous injuries, which further destabilize the joint. Most ankle fractures happen when the ankle is twisted inwardly or outwardly.
Symptoms of an Ankle Fracture
Ankle fractures can have any or all of the following symptoms:
- Pain in the area of the fracture. This can mean foot pain, lateral ankle pain or medial ankle pain.
- Swelling. This can be localized swelling near the site of the fracture or swelling of the entire ankle.
- Bruising, particularly over the site of the fractured bone.
- Blistering over the fractured area.
- Difficulty bearing weight on the ankle with an inability to walk without crutches or a walker.
- Open areas where bones have come through the skin. These are particularly serious and need surgery and antibiotics to prevent infection and heal the bone.
There are several different kinds of ankle fractures. In fact, there are two separate joints that can be involved in an ankle fracture. The first is the main ankle joint, which is where the three bones (tibia, talus and fibula) come together, and the second is called the syndesmosis joint, which is the joint between the tibia and fibula alone. This joint is held together by strong ligaments that keep the two bones from separating from one another.
In a lateral malleolar fracture, just the distal portion of the fibula is fractured. This is the most common type of ankle fracture and happens when the foot is forcibly inverted, either from a fall, twisting of the ankle, or from a motor vehicle accident. If the ankle is otherwise stable, an ankle brace or cast can be placed on the ankle and worn for about 4-6 weeks until the bone has healed. If the fracture has made the ankle unstable, surgery to put a plate and screws into the distal fibula might be necessary.
In a medial malleolar fracture, there is a break in the distal tibia at different levels of the tibia. A distal tibial fracture hardly ever occurs without a fibular fracture as well. If the fracture is not out of the proper position, it can be treated with casting. If there is a dislocation or abnormal alignment of the bones, surgery is required to fix the bones together.
In a posterior malleolar fracture, the back portion of the tibia is fractured. It is also associated with ligamentous disruption and fracture of the lateral malleolus in most cases. The ankle is often unstable and needs to be repaired surgically, especially if the broken piece represents 25 percent or more of the ankle joint. Arthritis is a common complication of this type of fracture.
With a bimalleolar fracture, two out of the three aspects of the malleoli are fractured. Many times, this involves a fracture of the medial and lateral malleolus together. This is an unstable fracture that requires surgery to correct alignment problems and to stabilize the joint. The ligaments supporting the medial aspect of the ankle are disrupted so that the ankle is not stable. After surgery, you will not be allowed to bear weight on the ankle for at least six weeks.
With a trimalleolar fracture, all three of the ankle malleoli have become fractured. Dislocation of bony fragments are common and this is a highly unstable fracture situation. Surgery is almost always indicated to correct this type of fracture situation. Pins and plates are used to realign the fracture ends.
In a syndesmotic injury, the connection between the tibia and fibula is lost and there is a fracture/dislocation. The fibula is fractured relatively high on the bone and the ligament that connects the two bones is disrupted. These fractures generally do not heal at all unless surgery is performed to put a plate in the fibular fracture and to connect the tibia to the fibula again.Causes of Ankle Fractures
Ankles can be fractured in any number of ways including:
- Motor vehicle trauma with impact to the foot or ankle
- Twisting the ankle
- Rotating the ankle
- Tripping or falling down due to a weak ankle
- Rolling of the ankle, also called an “inversion injury”
The doctor will examine the ankle for swelling, bruising and point tenderness over the fractured areas. Dislocations are almost always obvious as the joint does not look like it is in its proper position. A plain film x-ray can diagnose most ankle fractures, although nondisplaced fractures can be difficult to see at times. Sometimes stress is placed on the ankle so as to separate areas that are fractured but that don’t look fractured because the pieces are still in their proper alignment. A CT scan can be done of the joint if plain films are not accurate enough in identifying the broken fragments within the ankle joint. An MRI exam is especially helpful because it can show areas where ligaments have been disrupted along with the areas where the bones have been fractured.
Outcome of an Ankle Fracture
Because ankle fractures vary widely in severity, the outcomes can be variable. Simple lateral malleolar fractures heal very well without complications. Bimalleolar and trimalleolar fractures may take longer to heal and can result in arthritis. With physical therapy and rehabilitation, many people are back to walking and doing normal daily activities within 3-4 months, although some athletes do not experience normal recovery for up to two years. Driving is usually possible within 9-12 weeks following the fracture.
Physical therapy and rehab are important parts of ankle fracture recovery. You will be given home exercises to do after the cast or splint has been removed so that you can strengthen the ankle and prevent further sprains or fractures that can come out of having a weak ankle.
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