Revision total ankle
replacement

Unfortunately, total ankle replacements don’t last forever, and they may need to be revised.

Ankle replacements need to operate in a more complex biomechanical environment than hip or knee replacements and as a result are more susceptible to subtle malalignment or soft tissue imbalance. This can lead to problems that necessitate revision. The revision rate for ankle replacements has historically been higher than for hip or knee replacement but the gap is narrowing due to better implants, instrumentation, and surgical techniques.

The causes of ankle replacement revision are multiple, but the most common cause is Aseptic Loosening. This is where components loosen in the absence of infection. This loosening causes pain and swelling and drives the need for surgery.

Loosening can occur either early or late. Early loosening occurs when the components don’t bind to the host bone - this bonding is necessary for long term stability and if it fails to occur then components will loosen or subside (migrate) causing pain.

Late loosening can occur when wear particles from the  plastic lead to a low-grade inflammatory response that leads to cyst formation and if these get big enough then previously stable components can become loose causing pain. Newer plastic that has lead to lower wear rates in hip and knee replacement it is hoped will lead to a lower rate of aseptic loosening in total ankle replacement.

Infection can lead to revision. The most common situation is wound healing problems when the ankle replacement is inserted can lead to deep infection. That is why careful soft tissue handling and meticulous wound closure is critical to ankle replacement. Late infection is rare and is caused by bacteria in the blood stream from another source seeding in the joint replacement leading to infection.

If the alignment and soft tissue balancing is inadequate when the ankle replacement is performed this can lead to progressive deformity and instability that may lead to the need for revision. This is why restoration of alignment and correcting all sources of deformity with careful component placement and bone and soft tissue balancing is critical to a successful total ankle replacement.

Avascular necrosis is where the blood supply to the talus (ankle bone) is lost leading to death(necrosis) of the bone. This can lead to the collapse of the talus and the need for revision. The talus is a bone that is largely covered by cartilage above and below with limited soft tissue attachments that provide blood supply. This is why it is at risk with an ankle replacement. Fortunately, AVN is a very rare complication of total ankle replacement surgery.

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Revision ankle replacement requires Prophecy CT scanning - this allows us to develop a detailed operative plan to address the cause of the revision, correct deformity, restore stability and relieve pain. We now have a much more comprehensive suite of implants that can be employed to address each patients’ particular challenges. This is called the Invision Total Ankle Replacement.

In the past revision has sometimes not been possible because of the amount of bone loss particularly of the talus and as a result a hind foot fusion has been required as a salvage procedure. This has been technically difficult because of bone loss and there has been a high nonunion and patient dissatisfaction rate. Sometimes amputation is required because of unreconstructable defects in the bone or soft tissue.

At Macquarie University Hospital Limb Reconstruction Centre, we have been able to develop a custom designed 3D printed talus combined with a revision total ankle replacement. This has allowed us to provide pain relieving, deformity correcting, motion preserving and robust solution to a problem that in the past has required hind foot fusion (ankle and subtalar joint are fused) or amputation.

It is for these reasons that we are more confident that we can maintain an ankle replacement in our patients longer term as has been achieved in hip and knee replacements.

Dr Tim O’Carrigan