Questions and Answers about Ankle Replacement
At what age is ankle replacement an option?
The average age for ankle replacement is not much different than replacement of the hip or knee, around 60 years of age. In some disease entities, this age is much lower, especially in rheumatoid arthritis where age is really not a factor. Every effort is made to keep these patients as mobile as possible. The patients in their 30's, 40's and 50's can certainly be candidates for an ankle replacement if all of the criteria are met and the risks of this procedure are clearly understood. Even then, an effort is made to delay the surgery as much as possible. There does seem to be an opportune time to do the implant, beyond which surgery becomes increasingly more difficult.
How important is the type of implant?
The implant used for joint replacement is critical to the long-term success of the procedure. There are many different types of joint implants available around the world today. Some have been around for many years, while most have been developed more recently. While almost all of the currently available implants can provide excellent short-term results if implanted correctly, the bigger concern is how long they will last. Implants that have been around awhile have a track record that can be measured so that any problems that might occur have been documented, as well as the probabilities over time. Your surgeon should be able to discuss these issues with you and provide you with an explanation of which implants he uses and why.
What are the reasons ankle replacements may fail?
Ankle replacements can fail if they get infected or if excessive stress is placed on the joint. In other words, if the bone is weak, osteoporotic, of poor quality, or if the implant does not have optimal fixation, it can crush down into the bone eventually and result in failure. This is especially true in patients that do not have normal sensation in their ankle, such as those individuals with peripheral neuropathy from any cause. Diabetes mellitus is frequently associated with peripheral neuropathy, and, in those individuals, ankle replacement is probably not indicated. If it is performed, the implant has to be watched very carefully and possibly even protected with bracing or restriction of activity.
What are the possible complications?
Complications can occur with ankle arthroplasty. The most common complication is skin loss at the time of surgery. The skin around the ankle joint is very thin, and there is considerable swelling after an ankle replacement. Usually, however, small skin sloughs along the margin of the incision will heal without any skin grafting. Rheumatoid patients, in particular, are prone to having skin problems and great care must be taken at the time of surgery to preclude this.
Even with great care, occasionally the margins of the skin will slough. The most serious complication of all is infection. Should this occur, an effort can be made to salvage the joint by taking it out and using a spacer made of bone cement that contains an antibiotic temporarily in place of the joint. The joint may potentially be reinserted, but frequently a fusion is necessary. If the infection is severe, ultimately amputation may be necessary.
What happens once I decide to have surgery?
Following scheduling of the ankle replacement, the general medical tests are then carried out to clear the individual for surgery. This frequently includes lab work, chest x-ray, EKG, and so forth, and additional tests on the extremity to evaluate circulation and nerve function. Quite frequently, CAT scans, tomograms, or an MRI will be necessary to assess the quality of the bone around the ankle joint, as well as the status of the joint under the ankle and in the midfoot.
How long will the surgery last?
The surgery itself varies a great deal, depending on what is required. If the ankle has worn out in neutral, and if there are other deformities around the joint, the ankle can frequently be put in in two hours. If, however, there is heel cord tightness, if the ankle is tipped in or tipped out, if adjacent joints are bad, and if additional surgeries are required in all of these areas, the surgery can certainly go beyond that period of time.
What should I expect after the surgery?
The usual hospital stay following ankle replacement is two nights. Frequently, patients have gotten out of bed the day of surgery and are allowed to go to the bathroom if they are stable and have the ability to use crutches.
Range of motion or movement of the ankle is started on the second day and continued with no weight bearing for six weeks. At six weeks, an x-ray is taken of the ankle. If the position of the implant is good and if the tibia and fibula have fused together just above the ankle, then weight bearing is started. In individuals with very soft bone, and if their body weight is such that they would put extreme pressure on the ankle, occasionally weight bearing is delayed or at least slowed to allow the bone strength to improve.
Frequently, however, by three months after surgery, most patients are walking without any external aids and usually have no pain, although some aching in the joint will persist until the bone is strong enough to support the body’s weight. This can take six to nine months from surgery, and in some instances it can be associated with swelling.
Can I have an ankle replacement in the same ankle that has been fused?
A new ankle can be inserted in an ankle that has been previously fused, but not in all instances. Occasionally, where the ankle has spontaneously fused, where there has been no surgical intervention, the anatomy is such that the ankle can be inserted without too much difficulty. If the ankle has been surgically fused, the type of technique that was used will dictate to some extent whether or not an ankle can be inserted. If the small bone or the fibula was used to fuse the joint, and there is no support laterally, a new ankle cannot be inserted. If the small bone was not used, and if the overall fused position is excellent, then usually it can be taken down after all of the risks have been carefully discussed with the patient. The results are varied in that some patients get good range of motion and are very happy with the end result, and in others the motion is not as good as expected.
Last Updated: 11/09/2007