What Is It?
An arthrodesis in the truest sense of the word means a joint fusion, hence why in lay terms an ankle arthrodesis is known as an “ankle fusion.” A joint is comprised up of the ends of two pieces of bone, ligaments (which hold the bones together), tendons (which attaches muscle to the bone), and cartilage (which cushions our joints). In a nutshell, it’s a surface where two bones connect. Joint classification and composition can vary, but this is the simplest description. The two main bones that comprise the ankle joint are the tibia (long bone of the lower leg) and the talus (the ankle bone). Together they form the surface which allows you to pull your foot up or down. The ankle joint however is actually quite complex and other structures help to provide stability while standing and with movement (such as the fibula and ligaments).
Most importantly, wedged in this gap between the talus and tibia is cartilage. Cartilage provides the cushioning in the joint and allows for ease of movement. Cartilage cannot be grown back so overtime it wears down. The more active an individual is the quicker and more aggressive becomes the degeneration of cartilage. Degeneration of cartilage leads to arthritis, a condition of pain within the joints. Since there is no cartilage to cushion the bones, they grind together which causes pain, swelling and inflammation. Sometimes range of motion becomes limited as a result. Increasingly severe levels of pain are typically symptomatic of advanced levels of arthritis.
Different Types of Arthritis
However it is important to point out there are many different types of arthritis. The arthritis that is described above is known as osteoarthritis, but you might see it abbreviated as OA for short. There are other factors that contribute to OA, such as heredity and obesity, but OA is most significantly a mechanistic condition that results in the wearing down of cartilage overtime. Sometimes a patient develops OA due to a severe injury to the joint that damages the cartilage or destroys it entirely (also known as post-traumatic arthritis). In comparison, Rheumatoid arthritis (RA for short) is an autoimmune disease that results in the destruction of cartilage by the body’s own immune system. RA and OA are the two most common types of arthritis. If patients are signed up for an ankle fusion, it’s usually because they are faced with late stages of arthritis; typically OA. Therefore, patients presenting for an ankle fusion are usually in their mid forties and older.
By fusing the ends of the talus and tibia together, the joint is effectively eliminated. You lose the ability to move your foot up or down, but with no joint present the bones no longer grind into each other resulting in the absence of pain. In addition, some patients presenting for ankle fusion lack sufficient stability in their joints, which is remedied by fusing the bones together. The procedure varies with the surgeon’s technique, but typically the ends of the bone are first shaved off to create a flat surface. Then, the ends are fused together with internal fixation (such as screws, rod or plate) or external fixation, or sometimes a combination of both. Healing time for a healthy individual should be about three months, though age and other existing medical conditions can also factor into healing time. Smoking and diabetes for example are known to have an impact on healing. Therefore, depending on the forces at play, healing could take anywhere from 3-6 months. Sometimes factors like smoking and diabetes can result in complications such as failure to heal or misaligned healing. This could lead to the need for a revision of the fusion or more aggressive treatments, such as the injection of bone marrow to help stimulate healing.
Recovery is usually straight forward. Patients are expected to be non-weight bearing for the first few months of their treatment. Their surgeon will check on their healing progress periodically and will guide the patient to progress to partially weight bearing when appropriate. For the typical patient, this could be between one and a half to two months post-op, though again this varies per individual. For patients who have been fused with internal fixation, it might be possible to remove the hardware down the road. This all depends if the hardware becomes painful, or based solely on the patients preference. A lot of times the hardware can stay in without impacting the surgical outcome.
Another possible outcome of having an ankle fusion is arthritis of the neighboring joint. Fusing the tibia and talus together can have an impact on the other joints that make up the foot and ankle and could lead to arthritic changes. This varies with the patient’s level of activity. More aggressive patients run the risk of wearing the neighboring joint out. It is possible to fuse these joints as well, though again at the expense of motion. There are many types of joint fusions that are possible in the foot and ankle and all depend on the symptoms that the patient presents with. A patient may even need to have several joints fused at the time of their ankle fusion.
A fusion of the tibia and talus is also known as a tibo-talor fusion or TT-fusion for short. However, depending on the status of the talus (whether it’s healthy or damaged or not) it might have to be removed. This leads to an alternative type of ankle fusion known as a tibo-calcaneal fusion, or TC-fusion. This is a fusion of the tibia and heel bone, otherwise known as the calcaneus. This type of fusion typically results in a significant shortening of bone which leaves the patient with a leg length discrepancy. However, this could be remedied with a shoe lift. In addition, by fusing the heel, the patient’s range of motion is further decreased by eliminating the joint that is responsible for side-to-side swinging motion of the foot. If the patient’s talus is healthy, but they also have arthritic heel pain, they may receive a TTC-fusion which stands for tiob-talor-calcaneal fusion. Here all three joints are fused and eliminates all motion in the foot at the expense of being pain free.
Healing time for a TCC and TC-fusion are about the same for a TT-fusion; somewhere between 3-6 months depending on the patient. Full recovery can take anywhere from 4-9 months.
Almost always these operations require a non-weight bearing mobility device such as crutches or a knee walker.
Disclaimer: The information compiled in this guide was taken from sources made available to the public and from consultation with orthopedic surgeons. We are not medical professionals and do not regard ourselves as experts. Always listen to the instructions given by your doctor first and foremost. However, we encourage patient education and recommend that you research your injury further. Your medical institution website may have further useful information. Otherwise please check our list sources for more detailed reading.