Shoulder Info - Dislocations - Instability

What is it?

The shoulder joint is stabilized in part by the shoulder capsule, a series of ligaments that connects the humerus to the glenoid. When the ligaments weaken or tear, the shoulder has a greater tendency to dislocate. This is known as instability, which can lead to greater and more painful shoulder conditions, especially dislocation and subluxation.

Dislocation and subluxation are the telltale signs of instability. If either happens frequently, instability is usually to blame. Usually, a substantial blow to the shoulder can be identified as the start of the condition. Also, if the patient feels the shoulder suddenly give way or describes it as "unreliable," this may mark instability.

Normal shoulder joint.
Dislocation of shoulder joint. Head of humerus dislocates from glenoid.

Shoulder instability means your shoulder can dislocate or subluxate repeatedly during active movement or exercise. Subluxate means the joint moves more than it should do in normal circumstances but doesn't actually come out of joint. There can be a number of reasons for this and this will determine the type of treatment you will receive.

 Shoulder instability is divided into three main categories and this is largely decided on the first episode of dislocation.

1. Traumatic dislocation.
 This when the shoulder has undergone an injury with enough force to pull the shoulder out of joint such as being tackled in a rugby game, a road traffic accident etc. Usually this is the first episode and it would need reducing in A&E. You would be put into a sling for a period of time and then in some cases would undergo a course of physiotherapy.
Due to the amount of force that is associated with such an injury part of the joint called the labrum can be torn from the bone and this result in an unstable shoulder which may lead to further episodes of dislocation.  This would be an indication for a surgical procedure called an Anterior Stabilisation where the torn part of the labrum is repaired, following this a course of physiotherapy is needed to regain range of movement and strength.

2. Atraumatic dislocation.
This occurs when the shoulder dislocates with minimal force such as reaching up for an object or turning over in bed. Usually it will 'pop' back in itself or with a little help. Normally this type of dislocation does not need reducing in A&E. It can occur regularly throughout the day and will be associated with certain positions the arm is placed into. This type of dislocation is associated with people that have 'lax' joints, for example people who hyper-extend their knees and elbows and can get the palms of both hands onto the floor with ease.  This joint laxity is normal for these people and the onset of dislocation can be associated with a change in how the muscles around the shoulder are interacting with each other or a change in posture/ position of the arm. This can produce an imbalance in the control of the joint. Referral for appropriate physiotherapy is the initial form of management. The physiotherapist should look at the way in which the muscles and shoulder joint is moving and posture aiming to restore the balance. Treatment can 'cure' the problem as long as the exercises and advice is continued, but in some cases there is only minimal or nil benefit. At this point surgical intervention is indicated.

 3.  Positional Non-traumatic dislocations.
This group of people can dislocate their shoulders without any form or history of trauma. Some may have started out dislocating their shoulder as a party trick; others may have always had shoulders that just 'fall' out of joint. This type of dislocation is usually painless and can be put back in easily. Both shoulders are typically involved. The cause of this type of dislocation is usually a result of what we call 'abnormal muscle patterning' which means the strong muscles around the shoulder joint are not working in the correct order causing them to pull the shoulder out of joint with active movement in the particular direction such as lifting the arm forward above the head or out to the side and above the head.  The only treatment for this is physiotherapy that looks at re-sequencing the muscles in order to prevent further dislocations. 

Causes and Risk Factors

Often an initial subluxation or dislocation forces the ligaments of the shoulder capsule to be torn away from the bone (glenoid). If the initial condition does not heal properly, instability will result and worsen over time.

Risk Factors: Overhead and contact sports pose a greater risk of instability. Additionally, those with above-average joint laxity, or looseness of the ligaments, stand at great risk of shoulder instability.
Possible Causes: Injury and Trauma


Physiotherapy - to train the shoulder muscles to control the shoulder correctly and prevent further instability

Painkillers and anti-inflammatories - when pain occurs

Surgery - A number of procedures are available to remedy chronic instability, depending on the causes and findings on investigations.

o        Types of Surgery:

o        Arthroscopic Procedures - through keyhole surgery.

o        Open Shoulder Procedures - depending on the problems found.


Strong shoulder muscles remain the best defence against shoulder dislocation, subluxation, and, thus, instability. Exercises that build up these muscles around the shoulder should be done. Adequate warm-up before activity and avoidance of high-contact sports will help prevent of an instability-causing injury

  Shoulder Stabilisation Procedure

This is carried out under a general anaesthetic. It involves repairing the over stretched or torn ligaments deep around the shoulder joint. The surgeon may perform the surgery arthroscopically (keyhole), or as an open procedure. The doctors will discuss your individual surgery with you before the operation.

The operation involves reattachment and tightening of the torn labrum (blue) and ligaments (green) of the shoulder (see picture below). This usually done using sutures and small bone anchors.

View of the glenoid from the inside of the glenohumeral joint with the humerus removed. The blue area is the labrum.

A Bankart lesion is a tear of the labrum off the glenoid bone (red)

For more details of the surgery and videos:
For Interactive Animations see Interactive Surgery - go to [Shoulder] then [Instability & Labrum Problems] and [Bankart Repair].

Some people who have dislocations due to loose shoulder joints (MDI) and no torn labrum may require a Capsular Shrinkage procedure.

Your Operation

You must not eat or drink anything after midnight the day before your surgery. When you wake up following the procedure you will be wearing a sling with a body belt (see picture). The sling should be worn under the clothes for 3 weeks. The body belt can be removed at 3 weeks and you can begin wearing the sling outside your clothing, but the remaining sling is to be continued for a further 3 weeks.  For more details on Living with a Shoulder Sling CLICK HERE

You will probably be in hospital overnight after your operation. A physiotherapist will see you in hospital to teach you the appropriate exercises. You may also see an occupational therapist to give you advice regarding the use of your arm.


A nerve block is usually used during the surgery. This means that immediately after the operation the shoulder and arm often feel completely numb. This may last for a few hours. After this the shoulder may well be sore and you will be given painkillers to help this whilst in hospital. These can be continued after you are discharged home. Ice packs may also help reduce pain. Wrap crushed ice or frozen peas in a damp, cold cloth and place on the shoulder for up to 15 minutes. Ensuring you cover the wound site with a piece of cling film to keep the area dry.


Open repair:  There is an incision at the front of the armpit within the natural skin crease. The stitch is dissolvable but is usually removed at 3 weeks. Keep the wound dry until it is well healed. This usually takes 3 weeks.

Arthroscopic (keyhole) repair: This keyhole operation is usually done through two or three 5mm puncture wounds. There will be no stitches only small sticking plaster strips over the wounds. These should be kept dry until healed. This usually takes 5 to 7 days.


For the first six weeks your sling must be worn in bed. Sleeping can be uncomfortable if you try and lie on the operated arm. We recommend that you lie on your back or on the opposite side, as you prefer. Ordinary pillows can be used to give you comfort and support. If you are lying on your side one pillow slightly folded under your neck gives enough support for most people. A pillow folded in half supports the arm in front and a pillow tucked along your back helps to prevent you rolling onto the operated shoulder during the night. If you are lying on your back, tie a pillow tightly in the middle (a "butterfly pillow") or use a folded pillow to support your neck. Place a folded pillow under the elbow of the operated arm to support that.


An appointment will be made for you to see a physiotherapist after your discharge and you will be seen by the Shoulder Team 3 weeks post-operatively.


For the first six weeks all activities of daily living for example feeding, dressing, cooking etc must be carried out using your un-operated arm. If appropriate an occupational therapist will be available to give you advice on how to do this.


Your physiotherapist and surgeon will advise you when it is safe to resume your leisure activities. This will vary according to your sport and level, as well as the period required to retrain your shoulder muscles with physiotherapy.

 Below is a rough guide: 

Swimming Breastroke
6 weeks
3 months
Golf   3 months
Contact Sport Includes rugby, horse riding, football, martial arts, racquet sports, and rock climbing 3 months


You will not be able to drive for a minimum of 8 weeks. Your surgeon will confirm when you may begin.


This will depend upon the size of your tear and your occupation. You will need to discuss this with a member of the Shoulder Team


Patient Information

+ Anatomy
+ Ultrasound
+ MRI Scan

+ Arthroscopy
+ Injections
+ Sports Injuries
+ Subacromial Impingement
+ Calcific Tendinitis
- Arthroscopic Subacromial Decompression
+ Shoulder Dislocations
Arthroscopic Stabilisation
- Capsular Shrinkage
- SLAP Lesions
+ Frozen Shoulder
- Capsular Release
+ AC joint problems
- ACJ Arthritis
   - ACJ Excision
- ACJ Dislocations
+ Rotator Cuff Tears
- Arthroscopic Repair
+ Shoulder Arthritis
- Surface Replacement
+ Shoulder Sling
- Living with a Shoulder Sling
Sling Application
- CryoCuff Shoulder Sling
+ Your Anaesthetic
+ Viscoseal
+ Patient Experiences


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