Overview of Triple Arthrodesis
The triple arthrodesis is a type of surgery that has a range of valuable uses, particularly for problems with the feet and walking. This ‘triple’ part of the name comes from the fact that the surgery includes fusing together three joints in the back part of the foot; the subtalar joint (where the talus and calcaneus bones meet), the talonavicular joint, and the calcaneocuboid joint.
This surgery has a good track record for working as it’s supposed to (it’s predictable), so often it is used as the main method to correct different problems with feet and enable patients to be able to walk confidently and without pain. In fact, in one study that followed people who had triple arthrodesis surgery, 95% of them were happy with how it went, even 44 years after their surgery.
However, there are some downsides to this surgery. It can result in a loss of movement range in the foot, which might mean that another type of surgery would be a better option, depending on the person’s needs.
Anatomy and Physiology of Triple Arthrodesis
The triple arthrodesis procedure is usually performed using two incisions, one on the inner side (medial) and one on the outer side (lateral) of the foot. During this procedure, the surgeon comes across various structures in the foot. On the outer side, the surgeon may come across two types of nerves, the sural and intermediate dorsal cutaneous nerve. Blood vessels that may be encountered include the tarsal sinus artery and veins that supply the extensor digitorum brevis, a muscle located in the foot. The surgeon might also come across muscles and tendons such as the peroneal tendons, the extensor digitorum brevis muscle, and the peroneus tertius tendon.
On the inner side of the foot, the surgeon usually encounters the posterior tibial tendon, which is located near its point of attachment. Other structures that might be encountered depending on the surgical technique include the deltoid artery and the artery of the tarsal canal, as well as the great saphenous vein and its smaller branches.
There has been a recent discussion about another approach to this procedure which involves making a single incision on the inner side of the foot and sparing the calcaneocuboid joint, a joint essential in foot movement. This approach is referred to as the ‘medial double’. It has several advantages such as avoiding damage to structures on the outer side of the foot, saving operating time, and reducing the cost of the surgery. However, disadvantages might include an extended dissection which might damage blood vessels supplying blood to the talar body, a bone located in the foot.
Why do People Need Triple Arthrodesis
A triple arthrodesis is a type of foot surgery often used to treat several different foot deformities and problems with walking. It is often viewed as a final option for treatment when other methods have been unsuccessful. There are multiple circumstances in which this surgery might be performed. Here are some examples:
- Severe flat foot caused by problems with soft tissues or changes in nearby joints. This is usually accompanied by significant pain.
- Arthritis, or joint inflammation, caused by injury or wear and tear over time, especially when it’s painful.
- High-arched feet (“cavus foot”) caused by changes in surrounding joints and associated with pain.
- A condition called Charcot’s joint that causes weakening of the bones in the foot and can lead to skin ulcers or a gait that makes it difficult to propel forward while walking.
- Tarsal coalitions, which are abnormal connections between two or more bones in the foot, that can cause pain or wear and tear of the ankle joint and surrounding joints.
- Persistent issues from clubfoot, a genetic condition where the foot is twisted out of shape or position. This can cause pain, joint degenerative disease, or a gait that makes it difficult to propel forward while walking.
They may also be considered for some neurological conditions which result in muscle imbalances and a walking style that lacks forward propulsion, such as:
- Charcot-Marie-Tooth (a genetic nerve disorder).
- Poliomyelitis (polio).
- Friedreich ataxia (a rare genetic disease that significantly alters muscle coordination).
- Spina bifida (a birth defect when the spine and spinal cord don’t form properly).
- Cerebral palsy (a group of disorders that affect balance and movement).
There are other surgical procedures that may be possible, which aim to preserve motion in the foot. So, the decision to perform a triple arthrodesis depends on the specific person’s health, how their disease has progressed, and what the surgeon feels is the best choice.
When a Person Should Avoid Triple Arthrodesis
There are certain conditions where a triple arthrodesis surgery is not advisable. These major obstacles include an ongoing infection in the body, a condition called acute Charcot arthropathy (a bone disorder related to nerve damage), or issues with blood flow (arterial insufficiency).
Acute Charcot arthropathy can be identified by several signs. These include a strong pulse in the foot, a hotter temperature in the lower leg, localized swelling, and loss of sensation. Other factors, such a history of nerve damage (neuropathy), X-rays showing bone decay, and blood tests indicating inflammation (like increased ESR), can also suggest this condition.
There are also some less absolute factors that may hinder the surgery. These include uncontrolled health issues, presence of arthritis in the ankle, or if the patient hasn’t tried non-surgical treatments yet. As with any surgery, it’s important for doctors to carefully choose the right patients and manage expectations after surgery to achieve the best possible outcome.
Equipment used for Triple Arthrodesis
The triple arthrodesis is a procedure that involves the joints in the rear of the foot and the ankle. It uses standard tools and materials that are commonly used in most procedures of this kind. Screws of different sizes are used to hold the joints together while they fuse. For example, screws between 6.5 mm to 8 mm in size are used for the joint beneath the ankle, while 4.5 mm screws may be used for the joints in the middle part of the foot.
There are many manufacturers that make unique tools for this procedure, including plates and staples for the middle joint of the foot. A thigh tourniquet, which is a band used to control bleeding, is used during the surgery. A machine called an intraoperative fluoroscopy is also recommended. This machine lets the surgeon see the placement of the joints and check the fixation or holding of the bones in real-time.
There are other special tools needed for this surgical procedure such as a lamina spreader or a Hintermann distractor. These are devices used to create space between the bones during surgery, making it easier for the surgeon to work.
Who is needed to perform Triple Arthrodesis?
One doctor, known as a surgeon, may carry out the operation, but it’s often better if a whole team is involved. This is because having a team can help make sure the patient gets the best results. The team would usually include a special nursing team to look after the patient before, during, and after the surgery (called the perioperative nursing team), a team that puts the patient to sleep (known as the anesthesia team), and a staff member who knows how to use the imaging machines (a radiology technician).
After the operation, it’s also important that a physical therapist evaluates the patient. They can help the patient manage any pain and assist them in achieving their goals in terms of movement and function as they make their recovery.
Preparing for Triple Arthrodesis
Before treatment, it’s essential to evaluate how well your foot and lower leg function overall. We look at your ankle’s mobility to ensure it can support a surgical procedure called arthrodesis, which is a fusion of the bones in the middle of your foot. We will examine your entire leg, not only to plan how well we will position your foot during and after surgery, but also to evaluate how you walk.
Usually, when you step, your foot moves about 10 to 15 degrees away from the center of your body. But other factors, such as the positioning of your knee, may influence how we align your foot during surgery. Understanding your gait – or how you walk – guides us in this decision process.
Before the surgery, we use X-rays of the foot while you are standing and from different angles, to understand your unique joint structure, possible distortions, and how much the foot bones need to be realigned. We may need these images to decide if we need to use wedges, or graft bone during the operation. We may also examine your heel using an X-ray to see exactly how much we need to correct the alignment of your foot to get it in line.
If we want a more detailed picture of your joints, we can use a CT scan. Newer technology like standing CT scans are also becoming more popular for this. Besides, we can use MRI scans to look at the structures inside your foot, like ligaments and tendons, a DEXA scan to check for bone weakness, or a scanogram to check if there’s any bad alignment of your leg bones. Your feedback about pain, the state of your disease, walking analysis, and X-ray results all help us decide if surgery is the best option for you.
Before the procedure, we provide detailed explanations of what will happen. Because the operation fuses the joints at the back of your foot, you may find walking on irregular terrain or going down stairs tough. Your gait or walking pattern may also change. It’s important to know that recovery after the operation may take up to a year.
How is Triple Arthrodesis performed
The patient will be lying on their back with a device called a tourniquet attached to their thigh. This is used to control blood flow. It is recommended to use general anesthesia to ensure the patient is asleep and feeling no pain during the operation.
The surgery starts with an incision on the side of the foot, from the ankle bone down to the base of the fourth and fifth toes. The surgeon will be careful to not harm the nerves found in this area. If a specific nerve is in the way, it may be safely removed. The surgeon will move a muscle called the extensor digitorum brevis, which lies over a cavity in the foot known as the sinus tarsi. Tendons, which connect muscles to bones, will be moved out of the way.
Next, the surgeon will locate and clear out the sinus tarsi. It’s filled with fat and fibrous tissue that must be taken out to give the surgeon a clear view of the joint beneath it. They will then release the attachments to the subtalar joint—the joint that allows for side-to-side movement of the foot. In the same direction as the incision, the surgeon will identify and free up the ligaments in the calcaneocuboid joint, which is located in the middle part of the foot between the heel bone and the cube-shaped bone.
After this, the surgeon will make a cut on the inner side of the ankle, extending down to the bottom of the navicular bone. There is a vein in this area and it will be moved upward. The surgeon will then cut the tissue of the talonavicular joint, which is where the foot and leg bones meet.
The surgeon will remove the joint surfaces by a set of tools such as curettes or osteotomes, keeping the original shape of the joint. It’s crucial to ensure that the cartilage tissue has been cleared enough and the bone is well prepared to make sure the fusion of bones goes as planned.
After preparing the talonavicular joint, the surgeon then works on the calcaneocuboid joint using the same tools. If the foot is deformed, a piece of the heel bone can be taken out to correct it. Finally, the subtalar joint is prepared for fusion using different tools to ensure the bone underneath is clearly visible.
When all joints are ready, the talonavicular joint can be moved and temporarily fixated using Kirschner wires or Steinmann pins, which are long, thin rods. The same tool is used to fixate the subtalar joint and the calcaneocuboid joint.
Once the foot is in the right position, the bones are bond together. Several screws will be used to secure the places where the bones come together. The final result should be the foot in a neutral position, with the heel slightly turned outward and the midsection of the foot slightly angled outward.
Once the surgery is complete, the cuts are cleaned and closed up layer by layer. Several different methods can be used to close the skin, and a tube may be inserted to drain any excess fluid and prevent clotting. After the procedure, the foot will be immobilized using a cast or a splint and the patient should not put any weight on it.
Possible Complications of Triple Arthrodesis
After undergoing a triple arthrodesis surgery, which fuses three different joints in the foot together, there could be a few complications:
- One common problem is wound dehiscence, where the wound might open up. This could be due to how the tissues were handled during surgery or a issue with blood flow. To manage this, doctors will provide intensive care for the wound after the surgery.
- Another complication is pseudo or non-union of arthrodesis sites. This means that the joints that were supposed to be fused together didn’t properly combine. This can happen if the joint wasn’t properly removed during surgery, or if there wasn’t enough internal stability provided. To tackle this issue, the doctors may recommend further immobilization after surgery, the usage of bone stimulation devices, or even another surgery.
- Non-union is most common at the talonavicular joint, which is one of the three joints that get fused during a triple arthrodesis.
- Another problem could be hardware failure, where the medical devices used in the surgery fail. This can occur if the patient isn’t properly immobilized after the surgery or because of non-union. If hardware failure doesn’t cause any symptoms, it may not need to be managed; but if it does, another surgery may be needed.
- Infection is another potential complication, which can be treated with antibiotics.
Though rare, the blood flow to the talus – a bone in the foot – could be interrupted during the procedure. This may result in the death of bone tissue, also known as osteonecrosis. If this happens, treatments such as ankle fusion, talectomy (removal of the talus), or a bone graft (where bone is taken from one part of the body to replace the lost bone) might be needed.
Improper positioning of the fused joints could lead to early development of arthritis in the ankle. If the arthritis progresses and causes pain, an ankle fusion surgery might be necessary to provide relief.
What Else Should I Know About Triple Arthrodesis?
The triple arthrodesis is a form of foot surgery that can be helpful for various foot issues and walking problems. Because it’s typically a reliable operation, doctors often use it as the go-to treatment for several foot deformities. It also enables patients to walk without pain and with more strength. A study revealed that about 95% of patients who had the triple arthrodesis were happy with the results.
However, like any surgery, triple arthrodesis has its drawbacks. One of these is the reduced movement in the foot after the operation, which might lead other patients to consider different treatments. Nevertheless, this procedure could be a suitable choice for many patients with severe foot deformities.