Total Ankle Replacement
The purpose of a total ankle replacement is to relieve pain in the ankle while still allowing the ankle to move. Often times, ankle pain is caused by arthritis, a condition that can take many forms and go by many names, including osteoarthritis, post-traumatic arthritis, and rheumatoid arthritis.
Dr. Doty currently utilizes the Scandinavian Total Ankle Replacement (S.T.A.R.), which was developed by Dr. Hakon Kofoed of Denmark. The S.T.A.R. is unique because of its 3-part design, instead of a 2-part design like other ankle replacements currently approved in the United States. It has an unconstrained mobile bearing spacer, which is designed to allow the bearing surface to settle into a more optimal position and mimic your natural motion. Dr. Doty trained in his fellowship with Dr. Michael Coughlin, who was the principal investigator in the FDA clinical trial which got the S.T.A.R approved for implantation in the United States starting in 2009.
Ankle Replacement vs. Ankle Fusion
When an ankle is fused, the damaged cartilage is removed and the tibia bone and talus bone heal together with bridging bone so the ankle joint is eliminated. This results in good pain relief, but also loss of motion at the ankle joint. When an ankle is replaced, the ankle joint is removed and replaced with metal (CoCr) and plastic (polyethylene) components. These components replace the damaged cartilage surfaces and are designed to maintain joint motion. By maintaining ankle motion, less excursion of other surrounding foot joints is required, which may lessen the propensity for developing arthritis in these other joints. The ability to move the ankle may also be important for maintaining a normal walking pattern. Activities such as walking on a slope, golfing, and hiking may be more difficult with an ankle fusion rather than with an ankle replacement. The pivotal study performed under the direction of Dr. Coughlin and Dr. Mann demonstrated that results of the S.T.A.R. are very gratifying. The functional results regarding walking, standing, and pain control were superior to ankle fusion. There were more complications with the total ankle replacement than with the ankle fusion, but this may be accounted for by the learning curve of the surgeons. Familiarity with the ankle replacement procedure has led to more accurate implantation and a reduction in complications. We now better understand how to appropriately balance the foot during the ankle replacement surgery to provide improved longevity to the life of the total ankle implants.
Selection Process for Total Ankle Arthroplasty
While these guidelines are not set in stone, they are important considerations when evaluating the candidacy of a patient for an ankle replacement.
- Ankle arthritis (osteoarthritis, rheumatoid arthritis or post-traumatic arthritis)
- Six months of conservative therapy including bracing and anti-inflammatory medication
- Limitation in activities of daily living due to ankle pain
- Maintenance of ankle motion
- Prior infection of the ankle
- Weight over 250 lbs
- Insulin dependant diabetes
- Peripheral neuropathy
- Vascular disease with poor wound healing
- Uncorrectable malalignment of the ankle or foot
- Young age
- High impact activities such as running or jumping
During your preoperative evaluation we will review your history and possibly any prior radiographs, MRIs, and CT scans. Even if you have existing radiographs, your visit will likely include new standing radiographs of your foot and ankle. We will answer any questions that you have regarding the ankle replacement surgery and we will be happy to discuss any other alternatives of treatment.
The Surgical Procedure
The surgical procedure for ankle replacement is performed in an operative suite with an anesthesiology team and an orthopaedic surgery team. Anesthesia is determined on a case by case basis, but most patients prefer to have a nerve block placed in the leg. The nerve block is left in place for up to three days for postoperative pain control. The surgical procedure usually takes about 2 hours. Sometimes additional procedures are performed simultaneously with total ankle replacement such as removing previously placed hardware, lengthening a tight Achilles' tendon, or balancing the foot. After the surgery, you will go to the recovery room for about an hour. Depending upon your age, medical conditions, how far you've traveled, and other factors, you will likely stay in the hospital overnight.
The native anatomy of the ankle joint on the left and a model with a total ankle replacement on the right
Ankle joint pre-surgery
Ankle joint post-surgery
Ankle joint pre-surgery
Ankle joint post-surgery
You will receive nursing care on the floor from our highly skilled nurses. An orthopaedic associate will see you each day. A physical therapist may also come to assist you in safely walking with crutches or a walker without putting too much weight on your new ankle. Much of the time immediately after surgery is spent resting and elevating your leg to decrease swelling. We generally recommend you keep your leg elevated as much as possible during the first week. You will be discharged from the hospital on post-op day 1 with a prescription for pain medicine to help control your pain as the nerve block begins to wear off.
You will not be able to put weight on your new ankle during the first three weeks after surgery and will need to use crutches, a walker, or a rolling knee walker to mobilize. You will be discharged home in a splint and then we will see you at 1 week to check your incision and place a cast. Your ankle is usually immobilized for 3-6 weeks in a cast to promote healing although most patients are able to begin putting weight on the ankle at about three weeks after surgery while in the cast. Typically, at six weeks following surgery, the cast is removed and you are placed in a post-operative walking boot and allowed to start ankle range of motion exercises. You will be seen again at twelve weeks after surgery to check your progression. Typically, visits after surgery are 1 week, 3 weeks, 6 weeks, 12 weeks, 6 months and yearly after that.
If you wish to proceed with an evaluation at our Chattanooga office, call 423-778-5995 to schedule an appointment. Prior to your visit, It may be helpful to send us any prior imaging or pertinent medical records. Consideration of whether you are a candidate for a total ankle replacement should not be rushed. We want to make sure that you have the adequate time and resources to make an informed decision. It is also important to make sure we have tried other conservative measures adequately, if there is any possibility of relieving your pain without an operation.
© 2015 Jesse F. Doty, MD - Reviewed: October, 2015
Dr. Doty is a foot and ankle fellowship-trained orthopaedic surgeon with an interest in providing musculoskeletal care to the lower extremity. Subspecialty training equips him to confidently address some of the most complicated deformities of the foot and ankle. He is well-versed in internal fixation as well as external fixation in treating chronic hindfoot and forefoot deformities.