When the failure of primary anterior stabilization surgery is determined by functional scoring following estimation of the increased risk of re-dislocation after primary stabilization surgery, e.g. by the WOSI scoring, according to clinical examination of shoulder range of movements and stability, it should be expected that the pathophysiology of the remaining glenohumeral instability is identified based on the risk factors and predictive scoring (ISIS system). Subsequentially, further patient management planning is required in order to address specifically the cause of the initial surgery failure, with the foreseen expectation of the final successful shoulder stabilization.
Since shoulder instability, pain on exhort, and stiffness are of less functional importance in patients with functionally low demands, palliative non-surgical treatment following failure of primary shoulder stabilization might be of value if the severity of the disability due to the unstable shoulder can be controlled in part by pharmacological means and physiotherapy to strengthen the dynamic shoulder muscle stabilizers. Obviously, this solution cannot be applied to patients with functional demands, regardless of their age.
Therefore, in most clinical circumstances, revision shoulder stabilization surgery is necessary following failure of primary surgery. Revision surgery is primarily directed at resolving glenohumeral instability and pain, but the revision stabilization procedure could compromise the extent of shoulder range of movements as a secondary outcome; this should be discussed with the patient, especially in regard to his/her future physical abilities. A substantial arsenal of surgical solutions exists for different underlying causes of primary surgery failure, and revision surgery should be planned accordingly.
Anterior labral repair with or without capsular plication is highly effective for shoulder stabilization in patients with ligamentous laxity. When primary soft tissue repair fails due to suboptimal anchor placement, unbalanced capsule redundancy, humeral side ligamentous damage, and small non-engaging Hill–Sachs lesion of less than 20% anterior glenoid deficiency, the anterior labrum repair (Bankart repair) and capsule balancing by arthroscopic approach should suffice for functional outcome. Using this approach, shoulder stability with a good range of painless movement is expected to be achieved with revision surgery.
When the inferior glenoid deficiency is less than 20%, a bony procedure is not always considered,3 but when the bony loss exceeds 30% of the glenoid surface, the general opinion is that bone block implantation on anterior is advantageous, either by coracoid tip transfer (with the attached conjoint tendon providing an increase in glenoid surface, supplemented by suspension of the conjoint tendon, thereby providing dynamic stability to the head of humerus, e.g. Bristow technique,17 Latarjet technique),18 or autologous tricortical bone graft, which increases the glenoid surface.
The consideration for tricortical bone graft implantation is logical as an alternative technique for treating glenoid deficiency after a previous coracoid transfer that failed due to its malunion or non-union, but it is expected to have a less favorable functional outcome due to the high risk of postoperative shoulder stiffness.19
In rare cases when bone loss exceeds 45% of the glenoid surface, prosthetic replacement of the glenohumeral joint should be considered since treatment by bone grafting for extensive glenoid damage is not enough for mechanical glenohumeral stabilization.
A decision-making uncertainty exists if glenoid bone deficiency is in the intermediate range of 20%–30%. Under such circumstances, there is lack of substantial reported clinical information for the favored surgical treatment, either by the less extensive soft tissue procedure or by bone block implantation. In this “gray zone” of uncertainty, the relevant demographic data and personal risk factors (gender, age, contact sports activity, extent of ligamentous laxity) might help in making the surgical decision.
If the primary surgical stabilization failed because of significant bone loss in the humeral head and/or the glenoid, a more complicated surgical technique is required during revision surgery.
In the case of primary stabilization surgery failure due to large humeral head bony damage (Hill–Sachs lesion) that involves more than 20% of the surface, especially if the bony lesion is of an “engaging” type, autologous bone grafting with or without a “remplissage” procedure (filling the defect with infraspinatus tenodesis and posterior capsulodesis) is the favored surgical method, preferably using the arthroscopic approach that is expected to prevent glenohumeral dislocation by preventing the engaging mechanism of humeral impression on a glenoid rim.20 In the extreme situation of a combined engaging Hill–Sachs lesion and a large anterior glenoid deficiency with an “off-track” humeral gliding Hill–Sachs lesion, the surgical procedure should address the Hill–Sachs lesion fill and anterior block implantation onto the glenoid.