- Common pattern
- Anterior (forward) dislocation
- Highest risk group
- Males under 25 in contact sport
- Re-dislocation rate < 20
- Up to 90%
- Key imaging
- MRI + selective CT for bone loss
- Surgical options
- Arthroscopic Bankart, remplissage, Latarjet
What shoulder instability is.
The shoulder is the most mobile joint in the body — a small, shallow socket carrying a large humeral head. That mobility is also its weakness: the shoulder is the joint most likely to come out. Instability refers to a pattern in which the humeral head moves abnormally in the socket. The spectrum runs from frank dislocation (the joint comes fully out and has to be reduced) through subluxation (the joint slips but reduces itself) to subtle "apprehension" with certain movements.
Most traumatic shoulder instability is anterior — the humeral head dislocates forward, typically when the arm is forced into abduction and external rotation (the tackler's arm, the surfer's wipeout). A small number of patients develop posterior instability, and a separate group have multidirectional instability from generalised joint hyperlaxity.
What happens inside the joint.
A first anterior dislocation typically tears the labrum at the front-lower part of the socket — the Bankart lesion. The labrum is a fibrocartilage rim that deepens the glenoid socket and provides an important static restraint. Once it is detached, the front of the socket loses its bumper, and the shoulder is more likely to come out again.
In repeated dislocations, two further problems develop:
- Glenoid bone loss — the front rim of the socket gradually erodes, removing bone that the labrum repair would otherwise sit on.
- Hill-Sachs lesion — the dislocated humeral head impacts the rim of the glenoid, leaving an impression fracture at the back of the humeral head.
The presence and size of these bone lesions is the single most important factor in deciding which surgical operation will work.
The risk of re-dislocation.
For a young patient (under 25) who dislocates in contact sport, the recurrence rate without surgery approaches 90%. For an older patient (over 40) the recurrence rate is much lower — often under 20% — but the risk of a co-existing rotator cuff tear is high. The decision about surgery is therefore very different in each group.
How the diagnosis is made.
The history is usually obvious: a specific dislocating event, often requiring a trip to the emergency department to reduce. Examination assesses apprehension in abduction and external rotation, the relocation test, and the presence or absence of generalised hyperlaxity. Imaging is essential:
- Plain radiographs in a trauma series.
- MRI (sometimes with intra-articular contrast — MR arthrogram) to characterise the labrum and any cartilage damage.
- CT scan with 3D reconstruction when bone loss is suspected — to quantify glenoid bone loss and Hill-Sachs depth.
Non-operative treatment.
For first-time dislocators outside contact sport, particularly older patients, a course of rotator cuff and scapular strengthening physiotherapy is reasonable. Activity modification, bracing in contact sport, and avoidance of the at-risk positions are added where appropriate.
Surgical options.
Surgery is recommended when the recurrence rate is high enough that the joint is unlikely to remain stable without it. Two main operations are used:
- Arthroscopic Bankart repair — keyhole repair of the torn labrum using small suture anchors. Suited to patients with minimal bone loss. May be combined with a remplissage to fill the Hill-Sachs lesion.
- Latarjet procedure — transfer of a piece of the coracoid bone (with conjoint tendon attached) to the front of the glenoid, restoring bone stock and adding a dynamic sling. Suited to patients with significant glenoid bone loss or a high re-dislocation risk profile.
The choice between these operations is driven by the imaging, the patient's age and sport, and the risk profile assessed at consultation.
Frequently asked questions.
I've dislocated my shoulder once — do I need surgery?
Not necessarily. The single biggest predictor of re-dislocation is age. A patient under 25 in contact sport has a very high chance of recurrence and is often offered early stabilisation. An older patient with a single dislocation can often be managed non-operatively first.
What is the difference between Bankart repair and Latarjet?
Bankart is an arthroscopic repair of the torn labrum, suited to minimal bone loss. Latarjet transfers a piece of bone to the front of the glenoid to restore bone stock — it is used when there is significant glenoid bone loss or a particularly high recurrence risk.
How long after a stabilisation can I return to sport?
Return to contact sport typically takes 4–6 months after arthroscopic Bankart repair and 6–9 months after Latarjet. The decision is functional, not purely time-based.
Can my shoulder dislocate again after surgery?
Yes, although the rate is much lower than without surgery. Reported re-dislocation rates after arthroscopic stabilisation in the right patient are around 5–15%; after Latarjet, 2–5%.
What if I've dislocated my shoulder many times?
Chronic recurrent instability is best worked up with imaging including a 3D CT scan to quantify bone loss. The choice of operation depends on the bone-loss picture and the demands of your sport or occupation.
References.
- Owens BD, Dawson L, Burks R, Cameron KL. Incidence of shoulder dislocation in the United States military. J Bone Joint Surg Am. 2009;91(4):791–796.
- Burkhart SS, De Beer JF. Traumatic glenohumeral bone defects and their relationship to failure of arthroscopic Bankart repairs. Arthroscopy. 2000;16(7):677–694.
- Hovelius L, et al. Long-term results of Latarjet–Bristow procedures. J Shoulder Elbow Surg. 2012;21(5):647–660.