Shoulder dislocation

What is shoulder dislocation?

Shoulder joint is ball and socket synovial joint formed between Glenoid (shoulder blade) and humerus (upper arm). It is most mobile joint of the body, which makes it inherently unstable. The socket (Glenoid) is quite shallow and covers only a third of the ball (Humerus). The glenoid labrum (fibro-cartilaginous structure) attaches to the periphery of the socket to deepen the socket and makes the joint more stable. The labrum besides increasing the contact area between the ball and socket, also produces a suction effect, maintaining intra-articular negative pressure and stabilises the joint. The joint is supported on all sides with ligaments, capsule and muscles.

When the ball of the humerus (upper arm) completely comes out of the socket of the shoulder (glenoid cavity) due to a strong force, this condition is called shoulder dislocation. When it comes out partially, it is termed as called shoulder subluxation. The force that can cause dislocation in the shoulder can be a fall, an accident or sports injury. When you have repeated strains or injuries in sports like swimming, volleyball, rugby, tennis or golf, or if you have loose ligaments (genetic predisposition, hypermobility and double jointed) that hold the joint in place, then you can have shoulder subluxations or dislocations.

 The arm bone can dislocate out in the front (anterior), back (posterior) or bottom (inferior) directions. Most dislocations in the shoulder joint are anterior dislocations (front) nearly 97 %, in which arm bone comes out of the socket and pushes forward. Posterior (back) and inferior (bottom) shoulder dislocations account for only 4% and 1% of all the dislocations. 25% of the shoulder dislocations are associated with other fractures in this area.

 

What are the symptoms of the shoulder dislocation?

You will feel severe pain in the shoulder joint. You will not be able to move your affected arm in any direction. Swelling, bruising, weakness and numbness are also common. There is often visible physical deformity at the site. You may feel that the shoulder is loose and may hear popping or clicking sound when you attempt to move it.

What complications can arise from shoulder dislocation?

  • Recurrent shoulder dislocation.
  • Axillary nerve Injury,
  • Brachial plexus injury,
  • Injury to Axillary artery ,
  • Fractures (30%) – humeral head, greater tuberosity, clavicle, acromion, glenoid
  • Bankart’s lesion: avulsion of the antero-inferior glenoid labrum along with antero-inferior glenohumeral ligament complex and joint capsule.
  • Hill-Sachs lesion: a posterolateral humeral head depression fracture
  • Rotator cuff injury.

 

How is it diagnosed?

Its diagnosis is made by detailed medical history, physical examination by your surgeon and an X-ray.  Most patients need additional investigations like CT arthrogram or MRI scan to evaluate fracture, loose fragments in the joint, bone loss and most importantly to assess the damage to labrum.

 

How is it treated?

It can be treated by non-operative or surgical methods. Non-operative methods involve closed reduction, immobilization, medications, rest and physiotherapy.

Surgery is indicated in

  • Fracture dislocations
  • Irreducible dislocations
  • Dislocation with a wound
  • Recurrent dislocations or subluxations
  • Recurrent shoulder instability
  • Associated injury to blood vessels, nerves and rotator cuff tendons

 

What are the non-operative treatments?

The non-operative treatment is done by closed reduction, immobilisation in a sling, pain killers and physical therapy.

  • Closed reduction means your physician will push the ball back to its original position i.e. in the socket of the shoulder joint. This will reduce your pain to a remarkable level. A mild sedative or muscle relaxant may be given before closed reduction to decrease the discomfort. Your physician will do an X-ray to confirm that your shoulder is back in its normal position. This is the first line of treatment in any shoulder dislocation.
  • A shoulder sling is applied to immobilize and to ensure rest to the affected joint. Immobilization helps in healing of the torn ligaments and reduce its recurrence rates.
  • The patient is advised to take rest and he can also apply ice packs(crushed ice or a pack of frozen peas packed in a cloth) on the affected area to relieve pain.
  • Painkillers like codeine and paracetamol are prescribed to relieve the pain during healing.
  • Anti-inflammatory drugs such as aspirin and ibuprofen, are prescribed to control swelling.
  • With the reduction of the pain, the patient is encouraged by the physiotherapists for gentle exercises for about 3 weeks, to maintain mobility. The elbow, wrist and hand should be kept mobile during the period of immobilization. The exercises are gradually progressed to strengthening exercises (Rotator cuff and scapular strengthening) to improve the muscle tone and strength around the shoulder.

 

What happens with non-operative treatment?

 Most young patients develop Bankart and Hill Sach’s lesion following shoulder dislocation. Bankart lesion is the damage to the labrum in the anterior and inferior part of the socket and if it does not heal back, the patients develop instability and apprehension with certain shoulder movements (overhead). Hill Sach’s lesion is a fracture of the ball (humeral head) that happens when it engages with the rim of the socket during dislocation. Both Bankart’s lesion and Hill Sach’s lesion increases the likelihood of further dislocations.

 In an assessment of 1324 shoulder dislocations the chances of recurrent instability is

  • 2 times more likely in men
  • 5 times more likely in < 40 years old
  • 7 times less likely in patients with associated greater tuberosity fracture
  • 7 times more likely in those with hyperlaxity

Chances of recurrent shoulder instability based on age:

<20                 Up to 95%

20–25             50–75%

25-40              40-50%

>40                 <15%

In elderly patients with shoulder dislocation, many have rotator cuff injury, this need to be assessed and managed appropriately.

 

 What does the operation involve?

 The surgery is performed under general anaesthetic as a day case. Majority of the patients have keyhole surgery (Arthroscopic), however few with complex injuries need open surgery.

  • Bankart repair: The torn anterior inferior labrum along with the capsule is attached to the socket with the help of bone anchors.
  • Remplissage: If the Hill Sachs lesion engage with the socket on external rotation of the shoulder, the rotator cuff tendons could be attached to the socket to prevent engaging. Though the patients have stable shoulder, they could lose some movements. This procedure is needed only in selective patients.
  • Bristow – Latarjet procedure: This is performed in patients with bone loss from the socket and failed/recurrence after Bankart procedure. The procedure involves removing a part of shoulder blade (coracoid process) and attach that to socket to increase the depth and radius of the socket. This will prevent the ball from slipping out of cup. Muscles attached to the transferred bone provides additional stability.
  • The Skin is closed using absorbable sutures. The operation takes usually 1-2 hours (depending of the complexity of the condition) and the majority of the patients are discharged on the same day after 4-10 hours after operation.

 

What happens after surgery?

  • The local anaesthetic/block wears off in 4 to 12 hours after surgery. Patients are given painkillers before the pain starts i.e. on return to home. It is continued for at least 48 hours after the first dose. Thus, most of our patients report little or any pain.
  • The initial aim is to provide comfort and rest to the arm with the use of a sling. You would notice that the sling has a strap that goes around your body and prevents you from reaching out (external rotation). This strap along with the sling has to be worn for 6 weeks and taken off only during physiotherapy.
  • Your physiotherapists will teach you pendulum exercises of shoulder, gentle exercises of fingers, wrist, elbow, and forearm. This is important to prevent stiffness, maintain normal motion of the joints near your shoulder and to help with healing.
  • You are reviewed again after the period of two weeks to check the wound and physical therapy are advised for rehabilitation.
  • More strenuous exercises and full range of movements are advised after 6 weeks. Your physiotherapists and surgeon will guide you for the choice and duration of the exercises on the basis of clinical assessment.
  • The wound should be massaged (typically after 2 weeks) using the moisturizing cream by the patient 3 times a day for 3 months once the wound is well healed. This reduces the scar sensitivity and scar-related complications (tenderness helps scar to mature).
  • You should be able to gradually start using your arm more, start swimming, driving in 6-10 weeks. It is advisable to avoid contact sports or any injury to the affected area for 3 months. The duration may increase or decrease based on the complexity of the injury and surgery.
  • Physiotherapy is important to return back to normal functioning and might take up to a year or two to regain full function.

 

Are there any risks?

  • Infection
  • Recurrence of shoulder dislocations
  • Shoulder pain
  • Stiffness especially in external rotation
  • Axillary nerve injury
  • Late arthritis
  • Non-union
  • Hardware problems- anchor or screw pullouts
  • Graft lysis
  • Glenohumeral osteoarthritis
  • Chondral injury
  • Frozen shoulder

 

What are the results of the operation?

The results for the surgical operation in shoulder dislocations are excellent. The chances of failure are 5-15% and it depends on the complexity of injury and technique of stabilisation. Majority of the patients return to preinjury level of activities. The outcome is more predictable in the author’s experience.

 

What happens if nothing is done?

If it goes untreated or not treated properly, it can lead to a recurrence instability/dislocation, habitual dislocation, bone loss from glenoid, Osteoarthritis, restriction movement and function.

 

When can I return to driving and work?

You can return to work between a week and 3 months & can start driving from 6-8 weeks in conservatively treated shoulder dislocation and post Bankart repair. Besides, depends on the nature of your job, complexity of the dislocation and the treatment involved, your surgeon will be able to advice.

Shoulder dislocation

  1. Anterior shoulder dislocation in a cyclist with greater tuberosity fracture
  2. Reduced in emergency department and treated conservatively with polysling
  3. 4 months follow-up – the greater tuberosity fragments has healed and patient regained full function back

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