Frequently Asked Questions about Total Ankle Replacements
Jeffrey Johnson, MD; Sandra Klein, MD; and Jeremy McCormick, MD have the answers to all of your questions about Total Ankle Replacements.
Click on the question to hear the answer.
1. What is Total Ankle Replacement?
A total ankle replacement is an artificial joint that resurfaces both sides of the ankle joint in order to relieve pain caused by arthritis and maintain range of motion of the ankle. The ankle joint connects the leg to the foot and is made up of a cartilage covered surface at the end of the tibia (or shin) bone which joins with a cartilage covered surface on the talus (or ankle) bone. A total ankle will replace the cartilage on these two surfaces with a metal on polyethylene “bearing” surface that are firmly attached to the bone. Motion between these two joint surfaces is what allows the up and down movement of the foot. When an ankle joint replacement is preformed it will only resurface the ankle joint itself and would not be expected to help arthritis pain that is coming from joints of the foot.
2. Who are the best candidates to undergo an ankle replacement? Who is not a good candidate?
The best candidate for an ankle replacement is a healthy person with ankle arthritis who has minimal or no deformity or malalignment of the ankle. In general, an ankle replacement will function best in patients who are less active and not overweight. Ankle replacements can wear out over time and may require a revision surgery or conversion to an ankle fusion. Some medical problems such as diabetes, poor circulation, skin sores, or heart and lung disease may put you at a higher risk of infection, wound problem or other complication after ankle replacement. In addition, a malaligned or crooked ankle and even some medications may increase your chances of complication. In these cases, ankle replacement may not be the best solution for ankle arthritis.
3. What are the advantages and disadvantages of total ankle replacement in comparison to ankle fusion?
Ankle fusion has been a solution for severe arthritis of the ankle for many years. This operation provides reliable long term relief of pain and can also be used to correct deformity related to arthritis. Although ankle fusion results in loss of motion at the ankle joint, most people walk normally without a significant limp. This loss of motion at the ankle, however, can potentially cause arthritis in other joints in the foot over years of time. The primary advantage of ankle replacement is the hope that preserving some motion at the ankle joint will provide more normal function and protect the other joints around the ankle from becoming arthritic. An ankle replacement does not restore normal motion, but it may allow just enough motion to protect the other joints of the foot. The disadvantage of ankle replacement is that the parts may wear out, loosen or break with use. It is possible that you will require additional surgery on your ankle depending on your age when the ankle is replaced. A well done ankle fusion can frequently last a lifetime.
4. Why are total ankle replacements (TAR) performed less often than some of the other types of procedures for ankle arthritis?
Previous designs of total ankle replacements have not provided consistently good long term results. However, new implant designs are currently available, and their early results are encouraging. Despite these encouraging results, most orthopedic surgeons are not yet ready to recommend TAR in all of their patients with ankle arthritis until longer term studies are completed. In addition, compared to the number of orthopedic surgeons who are performing total hip and knee surgeries, there are a smaller number of qualified orthopedic surgeons with the training and experience to perform a TAR. Lastly, despite encouraging results with total ankle replacement over the past 5-10 years and coverage by Medicare, many private insurance companies continue to deny coverage for the procedure by claiming that it is an experimental surgery. This further limits the number of patients that have TAR as an option.
5. Why do TARs sometimes need to be performed in two separate staged procedures?
Many patients who desire TAR for painful ankle arthritis also have arthritis or deformity of other joints in the foot. The primary goal for TAR is pain relief, and therefore any other sources of pain need to be addressed to expect a good result from surgery. Fusions of other, less essential, joints in the hindfoot or midfoot may be needed to achieve pain relief. In addition, if the ankle or foot has a deformity such as a tight Achilles tendon, an ankle that turns out, or a severe flat foot, the stress on the new ankle replacement will be excessive and can lead to an early failure. In some cases additional procedures can be done at the same time as the TAR surgery. However, in many cases, these additional surgeries are extensive and require healing time before the TAR is performed, thereby requiring two staged procedures separated by weeks or months.
6. If I have an ankle joint fusion now, can my ankle be converted to an ankle joint replacement in the future?
The short answer is, ‘yes’, in that it is technically possible, however it should be considered very carefully. If you are not experiencing pain at your ankle after a successful fusion, then conversion to an ankle replacement to obtain more ankle range of motion would not be recommended. On the other hand, if you have a painful ankle fusion with arthritis that has developed at other joints of the foot, then you might consider converting this to an ankle joint replacement. Conversion to an ankle replacement might also be considered in a patient whose ankle fusion has not healed, or has healed in the wrong position. However, you should proceed with caution when considering conversion of an ankle fusion to a replacement since it is an uncommon surgery that has increased complications and the results would not be expected to be as good as with a traditional ankle replacement.
7. How long can I expect my total ankle replacement to last?
Recent studies have shown as high as 90% of total ankle replacements are still intact at 5 years after surgery. This number drops to about 80% at 8 years after surgery. Longevity of the ankle replacement seems to be better in those patients who have less deformity of their ankle going into the surgery. The biggest concern is that good information on the long term outcome of total ankle replacements is not yet available. While results at 5 and 8 years are encouraging, we really do not know what the results will be at 15 or 20 years after the operation. The best estimate is that most patients will likely need some type of revision procedure 10-15 years after the original surgery.