Ankle instability is often functional due to the hindfoot varus deformity, without objective ligamentous laxity. In such cases correction of the overall deformity usually results in resolution of the instability symptoms.
Where ligamentous laxity is present a Brostrom procedure or one of its variants may be performed at the same time as calcaneal osteotomy to correct the hindfoot varus. An extended lateral approach allows both to be performed through the same incision. Alternatively a tenodesis such as the Sammarco anatomical reconstruction may be used for additional security. A peroneus brevis graft is fixed to the normal ligament attachment sites using suture anchors. Again, this is often performed in combination with a calcaneal osteotomy, hence an extended lateral approach is used.
A patient with a very weak cavus foot, such as in polio, may need an ankle fusion as well as hindfoot stabilisation with a subtalar or triple fusion. Such a complex fusion is usually easiest to stabilise with a retrograde nail.