Keys To Considering Ankle Replacement In The Treatment Of Ankle Arthritis

Author(s): 
Bob Baravarian, DPM, and Jason Morris, DPM

Ankle replacement is rapidly becoming a comparable option to ankle fusion in the treatment of ankle arthritis. Although ankle replacements in the 1970s did not fare well, the new generation of ankle replacements has provided an excellent option in the treatment of ankle arthritis. Indeed, ankle replacement has proven to be a better option than ankle fusion in the proper situations.

   Accordingly, let us take a closer look at the current options for ankle replacement, potential benefits of these devices and the current thinking on the use of the different ankle replacements available on the market today. It is important to remember that patient selection and proper placement of the implant are the keys to an ideal outcome.

   In general, our institute reserves ankle fusion for younger, very active patients who require a great deal of strength and stability from their ankle. Ankle fusions are also preferred for cases of severe angular deformities that may not be correctable with ankle replacement. If the ankle is not well aligned and will not become well aligned with bony or soft tissue procedures prior to placement of the ankle replacement implant, we often perform an ankle fusion.

   One should reserve ankle replacement for patients who do not perform heavy manual labor, are over the age of 45 (preferably over the age of 55) and have little to no ankle deformity. Although surgeons may correct some level of ankle deformity with soft tissue or bone realignment procedures, the ankle replacement patient of choice is one with an arthritic ankle that is well aligned.

   Of interest is the fact that patients who have arthritic hindfoot joints about the ankle seem to do better with an ankle replacement than an ankle fusion. This is due to the fact that an ankle fusion places greater stress on the surrounding joints, which may lead to further arthritic changes of the hindfoot joints. In contrast, an ankle replacement allows motion at the ankle, resulting in less strain on the surrounding joints.

A Guide To The Preoperative Assessment

Patients will often present to our offices with a preconceived notion of what procedure is best for them. This is important to address early in the relationship with the patient. It is important to explain the two procedures (replacement versus fusion) in detail, and the risks and benefits of each.

   One should ensure a thorough assessment of the patient’s vascular and neurologic status. If the circulation of the patient is poor, do not select an ankle replacement as the anterior incision and soft tissue complications associated with ankle replacement may not be in the patient’s best interest. Furthermore, a neuropathic patient with lack of sensation in the foot is not a good ankle replacement candidate and such cases have shown an increased rate of failure.1

   The dermatologic workup requires an adequate check of the skin for breakdown and quality. If the skin is of poor quality, the anterior ankle has a skin graft or flap, or if there are severe varicosities, these may be possible contraindications to ankle replacement.

   Finally, check the function of the muscles, ligaments, tendons and bones of the foot and leg prior to considering an ankle replacement. Address laxity about the ankle from previous ligament injury to build a solid platform for the replacement. If there is a non-functioning tendon, surgeons need to ensure the pull about the ankle is ideal. Finally, alignment of the bones must be ideal or surgeons should correct this prior to pursuing ankle replacement.

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