Total Ankle Joint Replacement
The ankle is a complex joint that has incredible forces acting on it with every step. With overuse, age, micro trauma, or severe trauma, the ankle can loose its supporting cartilage leading to severe ankle joint arthritis. End stage ankle arthritis can be significantly painful and debilitating. Ankle joint fusion was the gold standard treatment for severe arthritis. Although a fusion eliminates the associated pain, it restricts movement of the joint. With the advent of new technologies in total ankle joint replacements we area able to eliminate the pain, and restore some of the normal range of motion of ankle.
Dr. Soomekh is proud to be one of the ankle surgeons that have expertise in Total Ankle Joint Replacement Surgery aka Total Ankle Arthroplasty (TAA). The advent of ankle replacements has taken a long journey of trial and error over the last 30 years. The first generation of total ankle replacements gained popularity in the early to mid 1970’s. The culmination of years of research and development has significantly improved the technology and quality of ankle replacements. The weakness in the first generation of replacements has been in their poor materials and poor construction and design. Over time, the implants were found to have an inability to withstand the forces the ankle would go and the plastic material would deteriorate at a rapid pace and the metal would break down the bone around it. This would lead to implant failure and further debilitation. The additional research and understanding of the biomechanic complexities of the ankle joint has lead to improved implants and better implant materials allowing for dramatic improves in the quality and longevity of total ankle replacements.
With the advent of new technologies and an improved understanding of ankle function, the treatment of ankle arthritis has broadly changed in the past decade. Ankle replacement is rapidly becoming a comparable option to ankle fusion in the treatment of ankle arthritis. The new generation of ankle replacements has provided an excellent option in the treatment of ankle arthritis and has proven to be a better option to ankle fusion in the proper situations. It is important to remember that for the best potential outcome, patient selection and proper placement of the implant is key to an ideal outcome.
Patient Selection for Total Ankle Joint Replacement
Ankle replacement procedures work well as long as the proper implant is placed in the proper patient. Furthermore, proper patient selection for replacement versus fusion procedures is essential for the best outcome. In general, Dr. Soomekh reserves ankle fusions for the younger very active patients who require a great deal of strength and stability from their ankle. Ankle fusions are also preferred in those patients with severe angular deformities of the ankle joint, which is many times not correctable with a TAA.
When the ankle is not well aligned and will not become well aligned with boney or soft tissue procedures prior to the placement of the ankle implant, an ankle fusion is often preferably performed. TAA is reserved for those patients who are less active and athletic, do not perform heavy manual labor, are over the age of 45 (preferably over the age of 55), and have little to no angular deformity. Those patients that are very active put undo stress on the implant that can lead to its failure. Younger patients presumably have many more years ahead of them, which increases the chance of implant failure.
Although some level of angular deformity can be corrected with soft tissue and or bone realignment procedures, in a separate and prior surgery, the better patient will be one with an arthritic ankle that is well aligned in all three planes. It is interesting to note that those patients who have arthritis in other joints of the foot, (the midfoot and hindfoot), seemingly have more success with a TAA than an ankle fusion. This is due to the fact that the loss of motion at the ankle with an ankle fusion places greater stresses on the surrounding joints; this may lead to furthering the already arthritic changes of the other joints. A TAA allows motion of the ankle resulting in less strain about the already arthritic surrounding joints.
Pre-operative Planning for Total Ankle Joint Replacement
Patients will often present to our offices with a pre-conceived notion of what procedure is best for them. This is important to address early in the relationship between the patient and our doctors. It is important that the patient and our doctors have a thorough discussion and explanation of the risks and benefits between a TAA and an ankle fusion; and detailing the both procedures and their differences.
The clinical examination is the first step in determining a patient’s candidacy for surgery. A complete work-up of the vascular (blood supply) and neurologic status (nerve quality) of the patient is undertaken. If the circulation of the patient’s lower leg and foot is poor, an ankle replacement is not selected. This is due to the fact that the TAA uses an anterior (front) incision to the ankle, and the soft tissue complications associated with TAA may not be in the patient’s best interest. A patient with nerve loss (neuropathic) and lack of sensation to the ankle and foot is not a good candidate for TAA as such patients have shown to have an increased rate of failure of the procedure. The examination of the skin (dermatologic exam) is required to check for its adequacy and quality. An example of poor skin quality are in cases where a previous skin graft or flap was placed on the anterior ankle or when there are severe varicosities (varicose veins) noted. Finally, the function of the muscles, ligaments, tendons and bones of the leg, ankle, and foot must be examined for their strength and quality prior to consideration for a total ankle replacement surgery.
Any laxity about the ankle joint from previous ligament injury (multiple ankle sprains) must be addressed prior to any discussion of total ankle replacement surgery. Surgical repair or reconstruction of the ligament complex is critical in order to re-build the integral, solid platform that will surround the ankle and the replacement and keep the new ankle stable. Any non-functioning or weak tendon must also be examined and addressed to make sure the pull about the ankle is ideal. Finally, the alignment of the bones that make up the ankle joint must be ideal, and if they are not, then they need to be surgically corrected prior to TAA.
Proper imaging of the ankle joint is needed. In most cases, standard radiographs (x-rays) are sufficient to determine the level of arthritis and any compounding deformity to the joint. The alignment of the bones that make up the ankle joint and their bone stock (bone quality) are read from the films. The supporting joints of the foot are also evaluated for their positions and degree of arthritis. If there is a potential for cystic changes in the talus or tibia or signs of avascular necrosis, an MRI or CT scan may be ordered to further assess the ankle joint. In the case of avascular necrosis (dead bone), as long as the majority of the talus is healthy, an ankle replacement may be undertaken but if the talus is very damaged, an ankle fusion may be a better option. If there are severe arthritic changes of the joints surrounding the ankle, a potential rear foot fusion and ankle replacement may need to be performed in conjunction.
Types Of Ankle Joint Replacements
Dr. Soomekh utilizes three different ankle replacement options. The InBone® total ankle replacement by Wright Medical™, the Salto Talaris™ Tornier System, and the STAR™ Ankle by Small Bone Innovations. Each has slightly different characteristics and advantages and disadvantages. The determination of which implant is the best for the patient depends on many factors.
The InBone® TAA and the Tornier system are fixed ankle replacements while the STAR™ total ankle replacement is a mobile bearing system. Each has shown to have excellent results and each have pros and cons. The main difference between a fixed and a mobile bearing ankle replacement is that with the mobile bearing option, the plastic spacer material is not attached to the talar or tibial component and floats in between the two. This allows for some varus and valgus tilt within the replacement and the joint. It is suggested that there may be less stress on the joint and the components during movement and weight-bearing on the metal-bone attachment point of the implant resulting in less loosening and failure over time.
The fixed option has a plastic spacer that is attached to the tibial component, this does not allow for any varus or valgus tilt but allows for a long stem insertion into the tibia which has been suggested to add strength and prevent subsidence or impaction of the metal into the bone that can lead to failure. The choice of implant is a difficult one to make. The STAR™ and the Tornier implant are both very low profile. This means that there is less of the original bone that needs to be removed to allow for the replacement to be placed into the body. If the replacement were to fail and need to be removed there is then more of a potential to be able to convert to either a fusion or larger ankle replacement. On the other hand the replacement has an excellent implantation guidance system and rig that is used during the procedure that allows for precise measurements and cuts during the surgery. The long tibial stem that the system uses allows for excellent tibial stabilization of the replacement making it stronger. Both systems have had excellent results and are fairly easy to insert after a learning curve is mastered.
Dr. Soomekh has used the STAR™ ankle replacement in stable and simple ankle replacement cases which require minimal soft tissue or boney procedures. The STAR™ also has a more stable talar component, which we prefer in cases of severe talar arthritic changes or severe medial and lateral gutter arthritis. It is still unclear, however, if there is any major benefit to a three-piece mobile bearing implant. On the other hand, if there are any cystic changes in the tibia or if there is previous distal tibial fracture and the bone quality is not ideal, we prefer the InBone® ankle replacement as it has a far more stable tibial component. In addition, the InBone® ankle replacement has a better surgical guidance system which allows better positioning in more difficult ankles. Finally, in the case of a previously failed ankle replacement that requires revision, the InBone® is our preferred system. The new Prophecy® InBone® allows for a custom fitting to the system as well as less surgical time. In simple cases with no deformity and an older patient with little use of the ankle, the Salto™ Talaris-Tornier implant is an excellent option.
Correct patient selection and the proper surgical procedure are essential for ideal outcomes with ankle replacements. With the continued advancements in ankle replacement options, it will become easier to determine which replacement material is best for each type of patient.
Why Choose Dr. Soomekh for your Total Ankle Joint Replacement?
Dr. Soomekh is well versed in the 3 major types of ankle replacements on the market. This allows him the ability to offer the proper ankle replacement for each patient. He understands the function of the ankle and the need for all forms of conservative and surgical care prior to ankle replacement. Dr. Soomekh has perfected and reinvented these surgical procedures and techniques and is recognized by his peers as one of the top Ankle arthritis specialists and Ankle surgeons in the Los Angeles area.