Total Ankle Replacement
Ankle joint replacement, or Total Ankle Arthroplasty, is the procedure where the diseased ends of the bones at the ankle are resurfaced with a metal and plastic artificial joint. Total joint replacement is a technique that has enjoyed great success in treating arthritis in the knee and hip joints. New techniques and materials have led to a resurgence in interest in this procedure to treat ankle arthritis.
I have been doing Total Ankle Arthroplasty surgery since 1999. I have used several different artificial joints. We call the metal and plastic artificial joints "Implants" or "Prostheses". For a long time there have been problems with the techniques and also the types of implants that have been used for Total Ankle Arthroplasty.
I have recently been using a new prosthesis called the Inbone Total Ankle Arthroplasty. It was designed by Dr. Mark Reiley from Berkeley, California. This prosthesis has only been in limited use for 5 years. It is placed in the ankle with a new technique that is different from that used in previous ankle joint replacement surgery. The results when using this prosthesis are very favorable, but they are only short term so far.
I believe that this is the Best Total Ankle Arthroplasty that is available. The combination of an innovative prosthesis and a new intramedullary technique for placement into the joint make this an exciting alternative to those that were previously available:
Both the tibia (leg bone) and talar (ankle bone) metal prosthetic components are well-supported in the bone with stems whose length can be adjusted based on your anatomy. The prosthesis is built with modules that are constructed within your ankle, allowing for a customized fit.
The polyethylene (plastic) liner between the metal components is thickened, over 9 mm in width, and this lessens the chance of wearing out. It also minimizes the chance that your body will react to the implants by resorbing bone about it, which could cause a prosthesis to loosen.
There is wide coverage of the talus bone with the metal prosthesis to minimize subsidence into the bone.
An intramedullary guidance system is used to precisely align the cuts made in your bone for placement of the prosthesis.
The articulating (moving) surfaces of the prosthesis have been designed to mimic the normal ankle geometry, and thus closely replicate normal ankle motion.
I attended a special course in Denver, Colorado in November, 2007 to learn about using the Inbone prosthesis. Dr. Reiley came to help me on the first patient I treated at Sutter General Hospital in February, 2008. I do this procedure at both Sutter General Hospital and Mercy General Hospital. The Inbone company is now part of Wright Medical Products.
Total Ankle Arthroplasty has a place in the surgical treatment of ankle arthritis, but it may not be the best operation for all patients. Some patients will do better with an ankle arthrodesis, or fusion. The joint replacement is particularly useful in patients who have arthritis involving the other hindfoot joints in addition to the ankle. For those patients, the hindfoot may be treated with arthrodesis at the same time that the ankle can have the joint replacement. Total Ankle Arthroplasty is also best done in "older patients".
Surgery
This surgery requires hospitalization for at least one night, and often two. You will require a general anesthetic or spinal anesthetic.
During surgery for the Inbone ankle a single incision is made at the front of the ankle extending for about 5 inches. A small cut is also made on the bottom of the foot just in front of the heel pad.
The metal and plastic prosthesis is built from small modules. The metal stem in the tibia is "built" inside the ankle. Next, the talar tray and stem are fixed to the talus bone. Finally, a polyethylene spacer is placed between the metal ends.
Day of Surgery
At the end of the procedure the wounds are covered and a short leg plaster splint is applied. That dressing gives support to the ankle, holding it securely. That should be left in place until I change it at the first post-operative office visit.
You will be given crutches or a walker at the hospital, and I want you to not put any weight on that leg for 6 weeks. In the hospital a physical therapist will instruct you in using the crutches or walker. Do not walk on the splint.
You should keep your foot and ankle elevated as much as possible to minimize swelling.
When your pain is under control, and you can safely get around without putting weight on the ankle, you may go home. Look here for things to watch for after inpatient surgery.
Post-operative Course
The first post-operative visit is usually 7 – 10 days after surgery. At that time I will remove the splint and dressings, wash your leg, and take out the skin staples or stitches.
I will then put your leg into a short leg cast. This is not a walking cast, so you will still need to use the crutches or walker. You will wear this until 6 weeks after the surgery. Do not walk on the cast.
The second post-operative visit is usually at the 6 week point. At that time I will remove the cast, and check to make sure that everything is healing satisfactorily. I will then have you go into a CAM Walker, and you will wear that for protected weightbearing for an additional 6 weeks. You must wear it when you do any walking.
I will ask to see you next after an additional 6 weeks, the 3 months point after surgery. I will have you get an Xray then to make sure that the joint replacement is healing satisfactorily, and there are no problems with the implants. I will allow you to go into a regular shoe then.
Most people “wean” off the CAM Walker and back into a regular shoe. This takes a variable amount of time, and depends on how comfortable the regular shoe feels. It may take a few days, or up to a month.
Most patients have swelling about the surgical area that lasts for about 4 months after surgery. It generally takes 9 – 12 months for complete healing to occur.
Final Results
The goal of the surgery is to leave you with a painless ankle that will allow satisfactory motion for normal activities. How successful that will be is variable. It is usually possible to make the ankle pain-free for daily activities. Most patients will have some degree of soreness that is hopefully mild. Most patients will notice discomfort when the weather changes. Most ankles will ultimately move through about 30 degrees.
You should avoid significant impact activities like running or jumping after this operation.
Complications
Complications can occur with any surgery. Go here for a general discussion of Surgical Complications.
Specific risks of this surgery include the possibility of the bone above the ankle not healing, or non-union, and implant problems.
The implants may become loose from the bone, and if this occurs it is usually accompanied by pain. If the implant breaks or loosens, you may need to have another operation to remove and replace the implants, or to fuse the ankle joint.