Ankle Arthrodesis

There are many surgical techniques for performing an ankle fusion that depend on factors such as the amount of deformity of the joint, the extent of the arthritis, and surgeon preference. Each accomplishes the same goals. The techniques include:

Open Method: The most common way that an ankle fusion is performed is by making an incision through the skin to open the joint. A cut is made on each side of the ankle – about 3-4 cm long on the inner side of the ankle and about 10cm on the outer side. Once the joint is opened, the surgeon uses a surgical saw to remove the articular cartilage surfaces of the ankle joint. Once the articular cartilage is removed on both sides of the joint, the body will try to heal the two surfaces together just as if it were fractured or broken.

It is important when the surfaces are removed that the angles of the cut surfaces are correct. Once the cuts are made the bones must be held in place while they fuse. This can be done using large metal screws and metal plates if necessary. The screws are usually under the skin and are not removed unless they begin to rub and cause pain.

In some cases, especially if the fusion is being done because of an infection or a failed initial fusion, an apparatus called an external fixator is used to hold the bones together while they heal. This apparatus has metal pins that are inserted through the skin and into the bone. The metal pins are connected to metal rods and bolts outside the skin that hold the bones in position while the ankle fuses. The fixator is removed after the bones have healed, usually in 12 to 15 weeks.

Arthroscopic Method: The arthroscope is a miniature TV camera that is inserted into the ankle joint through a small incision. Using the arthroscope to watch, other instruments are inserted into the ankle joint to remove the cartilage surface. The cartilage surface is removed using a small rotary cutting tool. Once the surfaces are prepared, screws are placed through small incisions in the skin to hold the bones together as they heal, or fuse. This procedure is merely different from the open procedure except that the incisions are smaller.

The benefits of this surgery include:

• It helps remove the surfaces of the ankle joint and allows the tibia to grow together, or fuse, with the talus.
• It is a very good operation for treating a worn-out joint.
• It lasts the patient a lifetime.
• It keeps the ankle joint from moving during walking and other activities, so the other foot joints will need good mobility.

An ideal Candidate for ankle fusion surgery is:

• Patient with severe arthritis of the joint
• Patient of any ages.
• Active patients, who may wear out the ankle replacement.

Ankle fusion surgery can not be performed on:
• Patients who can manage their symptoms with simpler, non-operative treatments.
• Patients who have had infections in the joint or in patients who are smokers. These patients have a high risk of developing a nonunion, a potentially significant complication.

Ankle fusion surgery is usually followed by a one night stay in the hospital to ensure the patient is comfortable. An ankle brace will replace the cast after 8 to 12 weeks. Your surgeon will take X-rays frequently to see if the bones are fusing together. You will probably need to use crutches for most of the time you wear the cast. As the fusion grows stronger, you will begin to put more weight on your foot when walking. You may need the help of a physical therapist to learn to walk smoothly and without a limp.

Once the fusion has completely healed, you will be fitted with several special shoe modifications to make walking easier. An insert in the shoe called a SACH foot is sometimes useful to help you walk more normally. This heel cushion compresses as you put your weight on the foot and allows the foot to roll more normally as you step. Another useful modification of the shoe is a rocker sole. Unlike a typical flat shoe sole, the rocker sole is rounded, allowing your foot to roll as you move through a step.

While deciding on the surgery, you should be familiar with
• The process
• The symptoms related to the surgery
• The risks and the complications of the surgery
• The benefits of the procedure
If you have any doubts, you should clear them up before deciding to undergo the surgery.

Once you have decided to undergo the surgery, your surgeon may suggest a complete physical examination by your regular doctor. This exam helps ensure that you are in the best possible condition to undergo the operation.

While preparing for the surgery, the surgeon will advise you on several precautions for the surgery for example:
• Avoid any medicines that you have been taking
• Avoid smoking
• Avoid eating or drinking after the night before the surgery

The ankle fusion surgery can be performed under general anesthesia.

The risks and complications from the ankle fusion surgery are:

• Nonunion of the bones: It occurs when the bones that are being fused do not heal together. This is called a nonunion, or pseudarthrosis. (The term pseudarthrosis means false joint.) There are factors that tend to lead to nonunion, but even in the ideal patient, nonunion can occur. Patients who are smokers have a much higher rate of nonunion, and should carefully consider the risk of this possible complication. Smoking cessation can be helpful in lowering the chance of a nonunion.
This may require another operation to add bone graft and perhaps additional fixation. The bones need to be completely immobilized to fuse, so an external fixator may be needed to help hold the bones in position as they heal.

• Malunion of the bones: It occurs when bones heal in the wrong position. If the malunion is too extreme and causes problems with walking, another operation may be required to try to achieve a better position of healing.

• Anesthesia Reaction: This occurs when the anesthesia given during surgery causes a reaction with other drugs the patient is taking or with the anesthesia itself. This can affect lung function because the lungs do not expand as well while a person is under anesthesia.

• Nerve or Blood Vessel Injury: During surgery, it is possible that either the nerves of the foot or the blood vessels around the ankle can be injured. This may result in numbness in the foot if the nerves are injured. Severe injuries of the blood vessels of the foot could lead to the need for an amputation.

• Infection: Infection after the spine surgery may show up early, even before you leave the hospital which can usually be controlled by antibiotics.

• Wound healing problems

• Arthritic changes in the foot joints. Because ankle fusion limits motion, patients often develop arthritis in the joints of the foot down the road.

Furthermore, patients who undergo ankle fusion surgery may need to get their shoes modified for the rest of their life.

After the surgery, you may have to stay in the hospital for 2-3 days. During the time, you may experience some swelling in your ankle, and you will need to keep your foot elevated to help reduce the swelling. Once the swelling goes down and the incisions on your foot start to heal, you will be put in a plaster cast from your knee to your toes (a short-leg cast). You will need to wear the cast until the ankle has fused — usually 3-4 months. For the first 6 weeks you should not put any weight on your foot as it may disturb the healing joint. While in the hospital, a physical therapist will teach you how to walk with crutches without putting weight on your foot.

During the post operative care period, x-rays will be taken to monitor the healing of your fused ankle joint. When the x-rays show that the joint is fused enough to take your weight, the cast will be removed, and you will be given a brace to wear that will support you as you begin walking with weight on your foot again. You will have to wear the brace for about a month.