Up to 20% of patients can develop instability of the ankle after a sprain.

Instability of the ankle manifests as multiple and frequent episodes of the ankle “giving way” or “rolling over”. The symptoms may only occur during sport, running or walking on uneven ground, but in severe cases can occur even on level surfaces. There is often pain felt at the front or outside of the ankle, and sometimes swelling, associated with these episodes.

In most cases, the cause is “functional instability”, where the muscles stabilising the ankle have lost their coordination and control (“proprioception”). The symptoms can usually be treated very effectively with physiotherapy. However, some patients have “mechanical instability”, meaning the lateral ankle ligaments have healed inadequately in a lax position.

All patients are encouraged to go through a full rehabilitation programme, whichever the type of instability, but a small proportion will suffer persisting symptoms and require surgery.

There are several methods for reconstruction of the lateral ankle ligaments, but in the 21st Century, the most effective is the Brostrum / Gould procedure, or “anatomical” reconstruction. Often an ankle arthroscopy is perfomed at the same time, particularly if further problems are known or suspected inside the ankle joint, such as osteochondral lesions or impingement.