Ankle replacement is typically performed through a single incision over the front of the ankle. After safely dissecting down to the joint line the bone cut in the tibia is typically planned first. This can be performed either by alignment rods at guides at the time of surgery or by custom 3D printed guides based off of a pre-operative CT scan.
The top of the talus is typically removed next through similar means. After both the tibial and talar joint surfaces have been removed the implants are sized and the bone is prepared for insertion of components. Most ankle replacement components are “press fit” which means they are inserted without any bone cement. These implants are specially designed to have a layer of metal that is porous or very rough so that bone can grow into or on the implant.
The tibial component is usually made of a metal tray with a polymer piece fit to the tray. This acts as the new tibia joint surface. The talar component is usually made of a smooth, highly polished piece of metal which acts as the new tibial joint surface. Patients are allowed to put weight on their joint replacement right after surgery and are usually enrolled in physical therapy to ensure that they maintain ankle motion.
Treatment will typically start without surgery and includes NSAIDs, rest, activity modification, and bracing. As symptoms progress, however, surgical intervention may be able to improve patients’ pain.
There are several broad categories of treatment for ankle arthritis: temporizing, fusion, and replacement. The “temporizing” surgeries seek to provide more temporary relief of pain, but are less invasive. One such option is the ankle scope (or ankle arthroscopy) in which a small camera and tools are inserted into the ankle joint via small surgical cuts in order to remove loose or damaged cartilage pieces and scar tissue.
Another, newer, option is the distraction arthroplasty. This procedure involves pulling the tibia and talus apart (or distracting them) for a prolonged period of time to allow scar tissue to form in this space. This new scar tissue acts as a temporary buffer between the tibia and talus so that the two bones no longer rub on one another.
Another category of treatment are fusion procedures. Fusion aims to alleviate pain by stopping motion through the ankle joint. While fusion procedures are reliable in terms of pain control, and can be performed through smaller incisions, patients can no longer move their ankle after the fusion procedure is complete.
The third broad category of treatment is ankle replacement, otherwise known as total ankle arthroplasty. Ankle replacement involves removing the joint surface of both the talus and tibia and inserting implants made from metal and plastic. Ankle replacement is typically performed through a larger skin incision over the front of the ankle. The benefit of this procedure is relief of pain by removing the bad joint surface, while maintaining motion through the joint.
Ankle arthritis, also called osteoarthritis of the ankle, refers to a degenerative condition of the ankle joint in which there is progressive loss of cartilage between the talus and tibia bones (or the tibiotalar joint). As cartilage is lost and there is progressively more contact between the bones in the ankle patients will begin to develop pain in their ankle.
Arthritis of the ankle is typically caused by a traumatic injury such as an ankle fracture or dislocation. Less commonly patients develop arthritis due to a deformity in their ankle joint or from overload from excessive activity or obesity. This is referred to as primary osteoarthritis, and accounts for about 30% of ankle arthritis.
Patients with ankle arthritis typically report severe pain in their ankle joint after activity or prolonged periods of standing. Imaging of the ankle joint via xray will typically show loss of the space between the tibia and talus, indicating that the cartilage in that space has been lost.
The Wright Medical PROPHECY navigation system is a virtual surgical planning (VSP) process that starts with a pre-operative CT scan to define the specific dimensions of each patient’s ankle joint. From this scan custom made 3Dprinted tibia and talus cutting guides are made for use during the ankle replacement surgery.
This is designed to increase the accuracy of each bone cut and can save time during the surgery. The INFINITY ankle replacement components are designed to be low profile, thereby minimizing the amount of bone that needs to be removed during the surgery. Both the tibia and talus components come in multiple size and shape options to best fit each patient’s ankle.