Total ankle arthroplasty: how to decide?

The risks

A total ankle arthroplasty , as any for any arthroplasty, carries a certain number of risks, fortunately quite rare. It is essential to be aware of them before deciding:

  • Wear: the polyethylene component wears by natural friction against the metal part. This is its normal functioning.
  • Loss of anchorage: the implant no longer “holds” in the bone for various reasons.
  • Infection: when a bacterium comes into contact with the prosthesis, it develops and compromises the prosthetic functioning. The infection can occur in a variable time after the surgery, either by contamination from the operative wound, or by migration of a germ from another infected organ (urinary tract infection, dental, skin wound, etc.). Antibiotics are therefore delivered during surgery to minimize this risk.
  • Deep vein thrombosis: the use of a tourniquet during the surgery followed by an immobilisation by boot during 15 days, is at risk to form a blood clot (thrombosis) in the veins of the operated leg. The clot can then migrate to the lung, phenomenon called pulmonary embolism. A preventive treatment is set up for 15 days.

How long does an ankle prosthesis last?

The ankle prosthesis is an implant recently “mature” after 30 to 40 years of development and progress since the first generations. Current “3rd generation” implants offer reliable results. The most recent studies describe a survival of more than 90% at a 10-years followup. This means that 10 years after surgery, more than nine out of ten patients still have their prosthesis functional.
However, although reliable, it must be considered that the total ankle prosthesis remains an implant still under development.

Choosing between the different surgical options

The main alternative to the ankle prosthesis is the arthrodesis, also called fusion, which has been the reference solution until now. This trend has reversed since the development of the most recent ankle implants.
Arthrodesis is a definitive procedure whose short and long-term consequences are known and reliable. After surgery, an immobilization in a boot is mandatory with forbidden weight-bearing for 3 months. In the long term, walking adapts to the loss of ankle’s mobility, most often without limping. However, the disappeared mobility is partially transferred to the adjacent joints (subtalar, mid-tarsal, knee). They are overloaded and may also develop osteoarthritis. This is an argument in favor of total ankle prosthesis.

Conversely, the ankle prosthesis provides much simpler short-term follow-up, since full weight-bearing is allowed immediately after surgery. The long-term evolution (beyond 10 years) is the least well-known point. The prostheses’ lifespan that we observe today is related to the implants of 10 years ago. Improvements made since then are expected to extend the lifespan of today’s implanted protheses, but this should not be confirmed before the next decade. In case of failure, the ankle prosthesis is removed and “converted” into arthrodesis.

To make a decision the selection criteria are multiple:

  • patient’s age at the time of the intervention
  • functional request (sports…)
  • acceptance or not of the risk of new surgeries
  • etc …

Which surgeon for this surgery

The ankle prosthesis is a complex procedure because it requires a rigorous technique in a hardly accessible operating area. The surgeon’s technical skill matters a lot for this surgery.
What’s more, the number of total ankle prostheses implanted every year in the world is quite low compared to other joints’ prostheses such as hip and knee.
As a result, only surgeons who often practice this procedure have acquired the experience brought by the number and the repetition of this operation.

It is therefore best to contact surgeons trained for this procedure. This is all the more true as scientific studies have shown better results for teams with the largest annual number of patients.

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