We will conduct a randomised clinical trial with the primary aim of determining whether surgical intervention followed by physiotherapy rehabilitation improves pain and disability outcomes more than physiotherapy rehabilitation alone in patients suffering from atraumatic shoulder instability associated with bony/capsulolabral damage. The results of this study will have direct and immediate impact on clinical decision making by establishing definitively if patients presenting with joint damage associated with atraumatic shoulder instability should be referred for surgery before commencing physiotherapy rehabilitation. The results of this study may also result in significant cost savings to the National Health Service if surgical intervention for atraumatic shoulder instability does not result in greater improvement than physiotherapy alone.

A two-arm, patient, physiotherapist and assessor-blinded, randomised controlled clinical trial will be conducted. 140 patients will be randomly allocated into one of 2 groups: a stabilisation surgery group and a control group. Primary outcomes (pain and disability) and secondary outcomes (participant-reported improvement and incidence of shoulder dislocations) will be evaluated at baseline and 6, 12 and 24 months after randomisation. Additional secondary outcomes of shoulder rotation range of motion and strength will be evaluated 6 months after randomisation.

Inclusion Criteria:

• feelings of insecurity (apprehension) at their shoulder joint
• provocation of apprehension with drawer and apprehension tests
• evidence labral/capsular injury in the shoulder joint

Exclusion Criteria:

• a history of a high collision shoulder injury precipitating apprehension symptoms
• evidence of bony injury around glenoid rim/and or humeral head
• a pristine joint i.e. no evidence of any structural injury to the joint, capsule or labrum.
• a rotator cuff tear
• neural damage affecting the upper limb
• previous shoulder surgery