The rate of recurrence of anterior unidirectional instability is lower after coracoid bone-block than with other techniques, even if failures still occur with this difficult procedure. Failure may consist in recurrent instability (dislocation, subluxation, unstable painful shoulder) or despite absence of obvious clinical signs, in radiologic failure (non-union, fracture), biologic failure (osteolysis) or infection, all of which may require revision surgery or lead to late instability or subclinical chronic apprehension. Clinical, X-ray and CT assessment identifies the type of failure and may lead to a second surgery being discussed with the patient according to functional demand. Technical error is often implicated and is generally due to deficient coracoid preparation, insufficient conjoint and coracoid tendon release or problems of positioning and fixing the bone-block on the glenoid. There are 2 types of revision surgery. Iliac bone-block involves the same demands as coracoid bone-block; it stabilises the shoulder and provides very good functional results. Although less effective, anterior capsule repair can also stabilise the shoulder when associated to posterior Hill–Sachs lesion remplissage by infraspinatus tenodesis. Osteoarthritis of the shoulder may set in after any surgical revision and impair the result.