Glenohumeral joint is prone to instability, i.e. the humeral head may dislocate off the scapular glenoid plate especially in the anteroinferior direction. Surgical treatment of shoulder instability aims at restoration of shoulder stability. The purpose of this trial is to investigate the difference in outcome after arthroscopic Bankart operation compared with open Latarjet operation in the treatment of a residual instability after a traumatic primary dislocation in young males.

Inclusion Criteria:

1. Subluxation or fear of shoulder dislocation after a previous, reduced and primarily conservatively treated (for more than 3 months) traumatic anteroinferior shoulder dislocation, or redislocation after a primary shoulder dislocation.
2. Clinically documented anteroinferior instability (ie. a positive apprehension and relocation test (Jobe)).
3. X-ray (true ap, 30 degrees oblique ap, Y- and axillary projections), 2- and 3-dimensional computed tomography (2D and 3D CT) and magnetic resonance imaging arthrography (MRA) documentation of the joint.
4. Congruency of the shoulder joint on imaging investigations.
5. Young adult male patient 16-25 years of age (15 years < patient < 26 years ).
6. Patient's willingness for operative treatment.
7. Written informed consent from participating subject.

Exclusion Criteria:

1. Non-congruency of the glenohumeral joint on imaging investigations.
2. Concomitant dislocated fractures (requiring operative treatment) of the humerus or the scapula (other than Hill-Sachs lesion or bony Bankart lesion)
3. Severe grade 2 or above (Samilson et Prieto) osteoarthrosis of the glenohumeral joint detected in X-ray investigation.
4. A humeral avulsion of glenohumeral ligaments (HAGL) detected in MRA investigation.
5. Concomitant ipsilateral plexus or axillar nerve injury affecting motor function.
6. Life threatening other concomitant injuries (i.e. multitrauma patient).
7. Stiffness of the glenohumeral joint (restricted passive external rotation less than 30 degrees measured in standing position, arm at side).
8. Age under 16 or above 25 years.
9. Open physis with significant growth expectation.
10. Intellectual disability, history of seizures with high risk of recurrence, existing significant malignant, haematological, endocrine, metabolic, or rheumatoid disease.