Background: Ankle sprains are common with the majority resolving with simple measures. Some patients may have residual pain and instability caused by functional instability. Intraarticular scar formation has been implicated in these patients. Few studies have shown the effectiveness of arthroscopic procedure in treatment of this condition.

Aim: Our aim was to assess the role of arthroscopy in functional instability of the ankle.

Methods: We performed retrospective analysis of case-notes of patients who presented with functional ankle instability from 2005 – 2007 who had failed a trial of conservative therapy and who had ankle arthroscopy, provided there was no true instability as determined by EUA and stress xrays.

Results: Out of 77 patients with a mean age of 38.1, 5 patients had true mechanical instability. They underwent open repair of the lateral ligaments and were excluded from the study. 21 had steroid injections which gave temporary improvement in 11 of them but eventually all of the 72 remaining stable patients underwent ankle arthroscopy. 67 (76.7%) had significant amounts of scar tissue present which needed debridement, most commonly in the antero- lateral corner (58.3%). 52 patients improved (72.2%), 20 patients (27.8%) did not improve. 2 patients suffered a superficial wound infection. 17 patients had an osteochondral talar lesion. Of these, 14 patients improved, 2 did not and 1 patient did not attend follow up.

Outcome: Our study supports the role of arthroscopy in the treatment of functional ankle instability resistant to conservative treatment. Significant improvement in symptoms can be expected in about 70% of patients following arthroscopic debridement of scar tissue rising to approximately 90% if there is an associated talar osteo-chondral lesion. Ankle arthroscopy is associated with a low complication rate and should be offered to patients with functional instability when conservative measures have failed especially if an osteochondral lesion has been identified.