Question

why would it be more difficult to replace an ankle than a knee, or hip, or even an elbow or shoulder?

Answer 1

Ankle replacement is far from as predictable as hip and knee replacement.

The procedure is much more demanding, and one of the main problems seems to be the shortage of patients with disease requiring replacement surgery.

Another problem seems to be the understanding of correcting the entire hindfoot in order to obtain the correct alignment of the foot-ankle complex.

Still another problem is to stabilise the unconstrained resurfaced ankle joint. Solving these problems will certainly give better long-term results.

The advantage of a failed ankle replacement is that it may be revised if there is sufficient bone stock, otherwise it can still be fused. The result of the last option is certainly better than if a hip or a knee replacement cannot be revised/Wear problems in ankle replacements can be expected to continue with the available current materials, especially in malaligned and unstable ankles. It has been calculated that the amount of wear is the same as for a knee prosthesis New materials and surfaces may be foreseen, but with the complexity of the combined movements in the ankle joint, metal against metal is hardly one of them. Forgiving materials with no wear that can tolerate the impacts to the ankle joint are what we should look for