This is a pilot study designed as a prospective, randomized controlled trial comparing arthroscopic Bankart repair and Remplissage with an open Latarjet coracoid transfer for the treatment of recurrent anterior glenohumeral instability with subcritical bone loss.

Presently, consensus guidelines for the surgical management of anterior glenohumeral instability are lacking. While there has been continual evolution in available arthroscopic instrumentation, this has not translated to improvements in patient outcomes. Isolated arthroscopic bankart repair is often associated with unacceptably high rates of failure, with a recent systematic review identifying continued recurrence rates of 14.2%. Improved recognition of bone defects and identification of critical defect sizes that contribute to recurrent instability and failed stabilization have lead to improvements in treatment algorithms. It has been widely accepted that glenoid defects exceeding 20% of anteroposterior (AP) width and humeral head defects exceeding 30% of the humeral head width contribute to recurrent instability. For defects of this magnitude, isolated arthroscopic Bankart repair is insufficient in restoring joint stability, and more extensive procedures are required. This can include adding a remplissage to the arthroscopic Bankart repair or open allograft reconstruction for humeral defects; or Latarjet coracoid transfer for glenoid defects.

However, often patients present with combined 'bipolar' bone loss, where individual defects are subcritical in size. There is increasing recognition that the presence of this combined bone loss may lead to increased rates of failure with an isolated arthroscopic bankart repair. Currently, accepted treatment options for bipolar bone loss include a combined arthroscopic Bankart repair and remplissage, or a Latarjet coracoid transfer. While there is supportive biomechanical data for each procedure, and limited case series in the literature, there remains a paucity of high-quality evidence to guide treatment for this complex clinical scenario. Consequently, we aim to perform a pilot study designed as a prospective, randomized controlled trial comparing arthroscopic Bankart repair and Remplissage with an open Latarjet coracoid transfer.

Inclusion Criteria:

• anterior shoulder instability (>1 dislocation)
• age >14 years
• evidence of a Hill-Sachs defect on MRI or CT,
• < 20% anteroposterior glenoid bone loss

Exclusion Criteria:

• >20% anteroposterior glenoid bone loss
• significant shoulder comorbidities (i.e., osteoarthritis, previous surgery other than previous instability), active joint or systemic infection, significant muscle paralysis, rotator cuff or Charcot's arthropathy,
• significant medical comorbidity that may alter effectiveness of surgical intervention
• major medical illness,
• unable to speak French or English,
• psychiatric illness that precludes informed consent,
• unwilling to be followed for 2 years

Patients will be evaluated by a blinded study nurse, unaware of treatment allocation, for administration of baseline questionnaires, as well as subsequent post-operative questionnaires.