The normal shoulder
The normal shoulder consists not only of the glenohumeral joint (the humeral head within the glenoid) but also of the articulation between the shoulder blade and the chest wall (scapulothoracic joint), the joint between the shoulder blade and the collarbone (acromioclavicular joint) and, finally, the joint between the collarbone and the breastbone (sternoclavicular joint). Normal shoulder movement means that the scapulothoracic joint must move as well as the glenohumeral joint. During this movement the glenohumeral joint moves so that the humeral head rotates within the glenoid. Using the arm above head height, for example at work or in sport, loads the ligaments that stabilise the head within the glenoid. The normal humeral head is larger than the glenoid. This anatomy, which resembles a golf ball sitting on its tee before a shot, allows the wide range of motion that movement requires. The socket (glenoid) is made wider and deeper by a flexible rim of cartilage (the labrum) that runs around its edge. This increases stability by making the “socket” larger and deeper. The labrum also acts as an anchoring point for the ligaments that stabilise the shoulder joint during movement.
The shoulder ligaments span the space between the humeral head and the glenoid and act to limit excessive sliding of the head on the glenoid, as well as rotation of the head on the glenoid. The main ligament, called the inferior glenohumeral ligament, is similar to a hammock. It supports the humeral head in the same way that a hammock supports a person.
The role of the glenohumeral ligaments is to act as seat belts and airbags for the shoulder, limiting excessive rotation and sliding of the head out of the glenoid. Much of the stability during normal movement comes from the rotator cuff muscles compressing the head into the glenoid. The ligaments provide static stability, as they passively limit the extremes of motion, while the rotator cuff muscles provide dynamic stability by contracting and pressing the head and the glenoid together.
Normal movement varies widely: some people have loose joints and ligaments without having shoulder instability, while others have relatively tight ligaments and less joint mobility.
What is shoulder instability?
Shoulder instability occurs when the humeral head moves out of the glenoid during shoulder movement. This is associated with symptoms, typically pain and a sensation of the shoulder slipping out. If the head comes completely out of the glenoid, this is called a dislocation. If the head comes partly out of the glenoid, this is called a subluxation. Shoulder instability can result from a single injury, such as a fall or a tackle; it can also result from repetitive movements that stretch the shoulder ligaments, allowing the head to move partly out of the glenoid. Although flexibility or laxity of the shoulder is a normal part of how it works, some people are more prone to shoulder instability because of the natural laxity of their ligaments. Other people may be able to sublux or dislocate their shoulder by selectively contracting the muscles around it. These rare cases usually do not cause pain. Some patients may have glenoid hypoplasia, a congenital failure of the glenoid to develop to a normal shape and depth. This is a rare condition and may not appear until the second or third decade of life. Shoulder instability occurs mainly at the front, although in about 10% of patients it may be at the back. In another 5–10% of cases instability may occur in more than one direction. This is called multidirectional instability.
Traumatic anterior shoulder instability
Most cases of shoulder instability result from a single traumatic event, such as a fall or a collision in sport. The arm is often forced out of position, but some patients may not remember the exact position of their arm. When this happens, the patient may feel the shoulder come out of the joint or may simply have pain. It is not unusual to have a “dead arm” sensation, where the patient notices loss of feeling and control of the arm. The shoulder may come completely out of the joint (dislocation) or partly out of the joint (subluxation).
Sometimes the head may go back into place on its own, or the patient may find that they can put it back by moving the shoulder. If the shoulder stays dislocated, the patient needs to go to a hospital emergency department so that a doctor can put the shoulder back in place. This is usually done with intravenous sedation, so that the muscles relax and the humeral head can be gently manoeuvred back into position.
What is injured when the shoulder dislocates?
When enough force is applied to the shoulder to cause a dislocation, one or more injuries may occur to the ligaments, the cartilage or the labrum of the shoulder. The most common injury is called a Bankart lesion. This is a separation of the labrum from the rim of the glenoid. The result of this injury is detachment of the attachment point of the main (inferior) glenohumeral ligament.
In addition, the labrum, which deepens the glenoid, is also damaged. In some cases the ligament may be stretched on its own or in combination with a Bankart lesion. Finally, the ligament may actually tear microscopically.
Injuries associated with shoulder dislocation
In addition to injury to the labrum, other structures may also be injured in a shoulder dislocation.
Nerve damage
The brachial plexus is a network of nerves that runs across the front of the shoulder; when the humeral head dislocates, it can press on the nerves of the brachial plexus. This can lead to weakness and loss of sensation (numbness). One or more nerves of the plexus may be affected. The nerve most commonly affected is the axillary nerve, which provides sensation along the outer side of the shoulder and also carries the electrical signals that make the deltoid contract and lift the arm above head height. In about 80% of cases these nerve injuries recover fully, but recovery may take months.
Rotator cuff injuries
Rotator cuff tears can occur in patients over 40 after a traumatic event. However, such tears are rare in younger people. The reason is that with age the rotator cuff tendon weakens and can actually tear when stretched, as happens when the shoulder dislocates. It is very important for the doctor to carefully assess the strength of the rotator cuff muscles after a dislocation, and if a tendon injury is suspected an MRI scan should be performed.
Bone injuries
In some cases of severe injury, the rim of the glenoid may fracture, or the rotator cuff attachment on the greater tuberosity of the humerus may be pulled out of place. With multiple recurrent shoulder dislocations, and especially after one or more failed stabilisation operations, wear of the glenoid rim may occur, together with a defect at the back of the humeral head. The latter lesion is called a Hill-Sachs lesion.
Treatment of traumatic anterior shoulder instability
Conservative treatment with physiotherapy
After an acute dislocation, the shoulder is immobilised in a brace for a period that allows the pain and inflammation to settle. How long the arm should be kept immobilised is a matter of debate. Although some surgeons recommend 3 weeks of immobilisation to reduce the chance of recurrent instability, more recent studies have shown that this is not entirely true. In addition, the length of immobilisation does not affect the risk of future recurrence. The treatment we recommend therefore consists of immobilisation for 1 or 2 weeks, followed by a physiotherapy programme to strengthen the rotator cuff muscles. If the patient is an athlete, the physiotherapy programme continues until strength is normal and there is no pain or apprehension of dislocation when the arm is out of the brace. Return to sport then becomes possible. However, there is still a risk of recurrent instability, especially in young male athletes. A brace may be used to give the athlete a sense of security, but there is no evidence that it will prevent another episode of instability. The likelihood of recurrent instability depends mainly on age: a 40-year-old patient has less than a 50% chance of recurrence, whereas a 17-year-old patient may have a chance greater than 90%.
Surgical stabilisation of shoulder instability
Surgical stabilisation is indicated when instability recurs and becomes a chronic problem. The decision to operate after a first episode must take a number of factors into account. If there has been a fracture of the glenoid that remains displaced, surgery is indicated to restore stability and the congruity of the joint. In the absence of a fracture, the individual risk of instability and how it affects the patient’s sporting or general activities must be considered. If an athlete is young and takes part in contact sport, such as a combat sport, it must be made clear that conservative treatment may put them at risk of a second dislocation, and if this happens during the season it may mean the end of the season for the athlete. An alternative in this case would be to have surgical repair in the off-season, ensuring a lower risk of instability in the following season.
Arthroscopic versus open repair
When there is no bone injury, the aim of surgery is to restore stability by repairing the Bankart lesion and any other stretched or torn ligament. In the majority of cases this can be done arthroscopically, by placing anchors (plastic, metal or absorbable) in the rim of the glenoid. The sutures from these anchors are then passed arthroscopically through the labrum and the capsule. This restores the tension of the ligaments and the lost depth of the glenoid caused by the Bankart lesion.
Advantages of arthroscopic over open repair
Modern techniques and technology allow equivalent results with both methods. However, the arthroscopic method has major advantages. These include less pain than open surgery and the possibility of performing the operation under regional anaesthesia. With arthroscopic surgery there is no need to disturb normal tissues such as the rotator cuff, which may not be possible with open surgery. In addition, the risk of infection is theoretically lower with the arthroscopic than with the open method.
When is open surgery indicated?
In over 90% of cases arthroscopic surgery is possible. In the remaining 10% of cases, open surgery may be needed when there is bone loss or a ligament injury (rarely). With bone loss along the front wall of the glenoid, a soft-tissue Bankart-type repair has a high chance of failure. Instead, an open approach should be undertaken.
Shoulder instability: treatment of anterior shoulder instability
Conservative treatment
Conservative treatment should be considered as an option in anterior instability, especially in younger patients. This approach initially consists of a period of shoulder immobilisation. Physiotherapy then restores the range of motion and strengthens the rotator cuff.
The first consideration when attempting conservative treatment is the patient’s age. Rowe et al. found significantly higher recurrence rates in young patients. The recurrence rate in patients up to 10 years of age was 100%, falling to 94% in those aged 10 to 20, 79% in those aged 20 to 30 and 50% in those aged 30 to 40.
Physiotherapy should focus on isotonic strengthening before isokinetic strengthening. The first muscles to address are those of the shoulder blade and then the deltoid; later, strengthening should focus on the rotator cuff of the shoulder.
Surgical treatment
The indications for surgical repair of anterior instability are not clear-cut. The patient and the surgeon need to consider the level of activity and the natural history of the condition in order to “weigh up” the possible benefits of surgery.
If a patient has had an anterior shoulder dislocation fewer than three times, it is reasonable to have arthroscopic repair, as arthroscopic repair is associated with lower rates of post-operative shoulder stiffness but has higher recurrence rates.
In the case of many recurrent shoulder dislocations, the patient may choose open Bankart repair, which on the one hand is associated with some degree of stiffness but on the other offers lower recurrence rates.
There are many surgical options for repairing anterior shoulder instability, and arthroscopic repair is the least invasive. Open Bankart repair and the Latarjet procedure are two of the widely used open surgical methods.
Arthroscopic repair has some advantages, including a smaller incision, less post-operative pain, shorter operating time, less blood loss and preservation of external rotation, which is related to the condition of the subscapularis.
Arthroscopic repair
Careful patient selection has led to good results with arthroscopic repair. Good candidates for arthroscopy are patients with a discrete Bankart lesion, an intact inferior glenohumeral ligament (IGHL) and no significant capsular laxity. In addition, there should ideally be no associated shoulder injuries and no more complex type of instability (multidirectional instability).
Several factors are taken into account for a successful arthroscopic Bankart repair:
- Appropriate patient selection
- Correct mobilisation of the capsular tissues
- Suture repair at the edge of the articular surface and not on the glenoid neck.
- Recognition and treatment of any other injuries of the capsule and the labrum.
Finally, preoperative imaging will rule out a fracture of the glenoid (bony Bankart).
Arthroscopic surgery for a Bankart lesion begins with a final examination of the shoulder under anaesthesia. The patient is placed either in a sitting position (beach chair position) or in a lateral position. The joint is accessed through the posterior portal (posterolateral portal) to inspect the joint. A thorough examination follows before the anterior incision (anterior portal) is made.
The edge of the glenoid articular cartilage is abraded. The labrum, which has detached from the anterior rim of the glenoid together with the capsular tissues, is identified and advanced over the abraded area. The labrum is then fixed with anchors and sutures (usually at the “3, 4 and 5 o’clock” positions, if we imagine the glenoid as a clock face), followed by plication of the lax anterior capsule. The lowest suture is usually placed first, so that the remaining sutures allow additional tensioning (tightening) of the capsuloligamentous tissues. The knots are tied with the shoulder in internal rotation, followed by an intraoperative assessment of range of motion.
Open repair
Although the operation has evolved over the years, the open Bankart repair has remained essentially unchanged since it was first described by Rowe in 1978.
First, the patient’s shoulder is examined under anaesthesia to confirm that the patient truly has anterior shoulder instability and will benefit from the operation.
The incision runs from the coracoid process towards the axilla. The dissection continues between the deltoid and the pectoralis major, taking care of the cephalic vein. An osteotomy of the coracoid follows, to retract the short head of the biceps and the coracobrachialis for better exposure.
External rotation of the humerus exposes the subscapularis, and the vessels at the lower border of the muscle are ligated. The subscapularis is then separated from the capsule. With the humerus in full external rotation, a vertical incision is made in the subscapularis. In this way a large flap is available for the repair.
With the humeral head in a posterior position, the glenoid rim is abraded and freshened with a small osteotome. Three drill holes are then made at the “1, 3 and 5 o’clock” positions for a right shoulder, and at “11, 9 and 7 o’clock” for a left shoulder (if we imagine the glenoid as a clock face).
A double suture is passed through each hole, then through the labrum and part of the capsule, and tied. External rotation is then checked; it should reach 25–30° beyond the neutral position.
Finally, the wound is closed in layers, with repair of the subscapularis without shortening and reattachment of the coracoid process.
Latarjet procedure
The open Latarjet procedure is increasingly used as a solution for anterior instability due to significant bone loss of the glenoid (>21%).
An incision is made between the pectoralis major and the deltoid muscle to expose and prepare the coracoid process. The coracoacromial ligament and the pectoralis minor are released at their insertions, while the coracobrachialis and the short head of the biceps are left intact. An osteotomy of the distal part of the coracoid, about 1.5 cm long, is performed carefully so as not to injure the musculocutaneous nerve, which lies close by. With the arm in external rotation, the subscapularis is split along its length or detached from the lesser tuberosity, where it inserts. The bone graft is prepared and shaped so that it can be placed on the anterior and inferior part of the glenoid, and is secured in place with screws. As the coracobrachialis and the biceps remain attached to the coracoid process, they now act as a restraining factor for the joint. Finally, the subscapularis is repaired.
The Latarjet procedure has been reported to prevent recurrent instability in 99% of correctly selected patients. However, it has several drawbacks that can lead to complications, such as stiffness.
Postoperative course
After surgery, the shoulder is kept in a sling for 3–4 weeks. The shoulder may be moved into internal rotation and slight abduction for hygiene, but without external rotation.
After 4 weeks, the patient is encouraged to perform active movements of full flexion, while at 6 weeks internal and external rotation exercises with added weight begin. At three months full, unrestricted lifting is allowed, while athletes return to sport after 6 months.
At 3 months the patient regains 70% of external rotation and elevation of the shoulder. At 6 months, 75–100% of normal shoulder movement is seen.
Why and when is arthroscopic repair preferred over the Latarjet procedure?
- It is more suitable for patients with a Bankart lesion (labrum) but no bone loss.
- Less invasive method
- Fewer complications compared with the Latarjet procedure
Why and when is the Latarjet procedure preferred over arthroscopic repair?
- It has a lower recurrence rate than arthroscopic repair
- Faster postoperative recovery and return to sport
Remplissage technique
The word comes from French and means “filling”. It refers to fixing the infraspinatus with sutures into the Hill-Sachs lesion, i.e. the impaction fracture of the humeral head. This is an associated injury after an anterior shoulder dislocation. Remplissage is used as an adjunct after repair of the Bankart lesion, which coexists in the vast majority of cases. It is performed arthroscopically and is believed to reduce the risk of instability when there is bone loss at the anterior rim of the glenoid.
EVIDENCE: E.M. Wolf & A. Arianjam: Hill-Sachs Remplissage an arthroscopic solution for the engaging Hill-Sachs lesion: 2 – 10 year follow-up and incidence of recurrence. J Shoulder and Elbow Surgery 2014:814-20.
- 4.4% rate of recurrent instability
- No reoperations or complications (although a small percentage of patients are believed to develop stiffness)
Arthroscopic Latarjet procedure
The arthroscopic Latarjet procedure is a newer technique that follows the same philosophy but is performed entirely arthroscopically. It is more technically demanding, so the complication rate depends on the surgeon’s learning “curve” and experience.
Glenoid reconstruction with bone autograft
In cases of severe glenoid bone loss resulting from a traumatic dislocation or failed surgery, the glenoid is reconstructed with a bone autograft (usually an iliac crest graft). This is the most suitable operation when the defect is so large that it cannot be restored with a Latarjet procedure.
Arthroscopic treatment of shoulder instability
Professor Salmas was one of the first specialist shoulder surgeons in Athens when, in 1998, he returned from fellowships in Zurich, Switzerland, with the leading shoulder surgeon Christian Gerber, and in Boston with JP Warner, Professor at Harvard University and Head of the Shoulder Service at Mass General Hospital. In those early years the Professor’s practice was a referral centre for shoulder conditions. In the early 2010s the Professor was operating with great success on patients with advanced and recurrent shoulder instability. Since 2000 he has treated many difficult cases of shoulder instability.
Arthroscopic surgical treatment of shoulder instability – shoulder dislocation
In those early years the Professor’s practice was a referral centre for shoulder conditions. Since 1998 he has successfully operated on hundreds of patients with shoulder instability, the condition in which the shoulder dislocates repeatedly (recurrent shoulder dislocation). Many of these patients had previously undergone unsuccessful surgery at other centres.
Arthroscopic versus open repair
When there is no bony injury, the aim of surgery is to restore stability by repairing the tear of the labrum (Bankart tear) and any other stretching or tear of the ligaments. In most cases this can be done arthroscopically, by placing anchors (plastic, metal or absorbable) on the rim of the glenoid. The sutures from these anchors are then passed arthroscopically through the labrum and the capsule. This restores the tension of the ligaments and the lost depth of the glenoid caused by the Bankart tear. After surgery the patient keeps the operated arm in a sling for 4 weeks. Then, for the following 6 weeks, they follow a physiotherapy programme to fully regain range of motion and function of the arm.
The doctor will examine your case and recommend the right treatment.
Request an appointment210 7793103Frequently asked questions
Shoulder instability and dislocation: frequently asked questions
Didn’t find the answer you were looking for? Call us on 210 7793103.
Will my shoulder dislocate again after the first dislocation?
The risk of recurrence is high in young people and athletes. In older people it is lower, but the risk of a rotator cuff tear increases.
When is surgery needed?
When the shoulder has dislocated more than once or there is a high risk of recurrence. Arthroscopic stabilisation (Bankart repair) is the most common operation; when there is bone loss of the glenoid, the Latarjet procedure is preferred.
When can I return to sport?
Usually 4–6 months after surgery, depending on the sport and on how rehabilitation progresses.
Patient cases
Patients with shoulder instability and dislocation
Recurrent anterior shoulder dislocation – anterior shoulder instability – labral tear – shoulder arthroscopy or arthroscopic shoulder repair – Bankart Repair
Shoulder instability – shoulder arthroscopy – labral repair – Bankart Repair
Recurrent anterior shoulder dislocation – arthroscopic Bankart Repair
Recurrent anterior dislocation of the left shoulder – arthroscopic repair – 17 years after surgery
Recurrent anterior shoulder dislocation
Recurrent shoulder dislocation with a glenoid fracture (bony Bankart lesion) – arthroscopic repair
Shoulder instability, recurrent shoulder dislocation – 5 months after arthroscopic repair
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