Shoulder Dislocation: Causes, Treatment and Recovery

Frequently Asked Questions

What exactly is a shoulder dislocation?

A shoulder dislocation occurs when the top of the arm bone, known as the humeral head, completely separates from its normal position within the shoulder socket (glenoid cavity). This traumatic event most commonly involves the humeral head moving towards the front of the shoulder.

For a complete overview, see the comprehensive guide to shoulder pain.

What are the most common causes of a shoulder dislocation?

Shoulder dislocations are frequently caused by trauma, such as falls, sports accidents, or direct blows to the shoulder. They can also result from sudden or unnatural movements, pre-existing joint instability, or degenerative conditions like osteoarthritis.

What symptoms would I experience if I dislocated my shoulder?

You would typically experience intense, sharp shoulder pain, a visible deformity of the shoulder, and a significant inability or difficulty in moving your arm. Swelling, bruising, or a grinding sensation (crepitus) might also be present in the affected area.

How is a shoulder dislocation diagnosed?

Diagnosis involves a physical examination by a doctor to assess tenderness, joint mobility, and the presence of any deformity. X-rays are crucial to rule out associated bone fractures, while an MRI provides detailed images to evaluate potential injuries to soft tissues like ligaments, tendons, and cartilage.

What structures are affected during a shoulder dislocation?

A shoulder dislocation involves the displacement of the humeral head from the glenoid cavity, impacting several key structures that normally stabilize the joint. These include the joint capsule, ligaments, tendons, the rotator cuff muscles, and the cartilage that covers the bone ends.

For a broader overview of related conditions, see our our comprehensive shoulder pain guide.

Sources and Scientific References

1. Kearney RS et al. (2024). Acute rehabilitation following traumatic anterior shoulder dislocation (ARTISAN): pragmatic, multicentre, randomised controlled trial. BMJ. 384:e076925. DOI | PubMed
2. Liew Z et al. (2021). Development of a single-session physiotherapy and self-management intervention for the treatment of primary traumatic anterior shoulder dislocation for the ‘Acute Rehabilitation following Traumatic anterior shoulder dISlocAtioN (ARTISAN)’ multi centre RCT. Physiotherapy. 113:80-87. DOI | PubMed
3. Hayes K et al. (2002). Shoulder instability: management and rehabilitation. J Orthop Sports Phys Ther. 32:497-509. DOI | PubMed
4. Lahti A et al. (2016). [Shoulder dislocation]. Lakartidningen. 113. PubMed
5. Monica J et al. (2016). Acute Shoulder Injuries in Adults. Am Fam Physician. 94:119-27. PubMed

A shoulder dislocation is a traumatic event that involves the displacement of the humeral head from its natural position within the glenoid cavity of the scapula. Under normal conditions, the humeral head is held in position by a series of complex structures, including:

• Joint capsule: a fibrous covering that surrounds the joint.
• Ligaments: strong bands of tissue that connect bones together and stabilize the joint.
• Tendons: robust cords that connect muscles to bones and contribute to joint movement.
• Muscles: the rotator cuff, a group of four muscles that wraps around the humeral head and ensures its stability.
• Cartilage: a smooth tissue that covers the bone ends and facilitates smooth movement during motion.

Shoulder dislocation can occur in different directions, but the most common is anterior dislocation, where the humeral head moves toward the front part of the shoulder. Other less frequent types include posterior, inferior, and superior dislocations.

Causes:

The causes of shoulder dislocation can be various, including:

• Trauma: falls, sports accidents, direct blows to the shoulder.
• Sudden or unnatural movements: lifting excessive weights, sudden or uncontrolled movements.
• Joint instability: congenital or acquired ligamentous laxity, joint hypermobility.
• Degenerative pathologies: osteoarthritis, rheumatoid arthritis.
• Predisposing factors: previous dislocations to the same shoulder, muscle weakness, postural alterations.

Symptoms:

The symptoms of shoulder dislocation are generally obvious and include:

• Intense pain: sharp and shooting pain in the shoulder, which may radiate to the arm and neck.
• Deformity: the shoulder may assume an abnormal and unnatural shape.
• Functional impairment: the inability or considerable difficulty in moving the arm.
• Crepitus: sensation of grinding or popping during attempted movement.
• Swelling and bruising: swelling and bruising may appear in the shoulder area.

Diagnosis:

The diagnosis of shoulder dislocation is made based on:

• Physical examination: the doctor will evaluate tenderness, joint mobility, presence of deformity and other clinical signs.
• X-rays: useful to exclude associated bone fractures.
• Magnetic Resonance Imaging (MRI): provides detailed images of soft tissues and allows evaluation of possible injuries to cartilage, ligaments, tendons and muscles.

Injuries associated with inferior shoulder dislocation (anterior-inferior dislocation)

Inferior shoulder dislocation, also known as anterior-inferior dislocation, is a traumatic condition where the humeral head exits from its natural position in the glenoid cavity, positioning itself anteriorly and inferiorly relative to it. This traumatic event can cause various injuries to bone, cartilaginous, ligamentous and tendinous structures of the shoulder joint.

Bone injuries:

• Fractures: the force necessary to dislocate the shoulder can cause fractures to bone structures such as the glenoid (articular cavity of the scapula), the acromion (bony projection of the scapula), the humeral greater tuberosity (upper portion of the humerus) or the coracoid process (bony projection of the scapula).
• Impact injuries: the impact of the humeral head against the glenoid cavity or other bone structures during dislocation can cause bone contusions, erosions or even impact fractures.
• Hill-Sachs lesion: This is a specific compression fracture that occurs on the posterior (posterolateral) part of the humeral head. During dislocation, the humeral head is pushed against the anterior border of the glenoid cavity, causing a flattening or small bone deformity in this area. The Hill-Sachs lesion can compromise shoulder joint stability and increase the risk of future dislocations.

Cartilaginous injuries:

• Glenoid labrum injury: the glenoid labrum is a ring of cartilage that lines the glenoid cavity and increases its depth. Dislocation can cause tearing, crushing or detachment of the glenoid labrum.
• Glenoid rim injuries: the glenoid rim is a ring of fibro-reinforced cartilage that borders the glenoid cavity and contributes to joint stability. Dislocation can cause tearing, stretching or detachment of the glenoid rim.

Ligamentous injuries:

• Joint capsule rupture: the joint capsule is a fibrous covering that surrounds the shoulder joint and ensures its stability. Dislocation can cause rupture of one or more capsular ligaments, particularly the inferior glenohumeral ligament (IGHL) and the middle glenohumeral ligament (MGHL).
• Extra-capsular ligament injuries: the shoulder is also stabilized by extra-capsular ligaments such as the coracoacromial ligament and the coracohumeral ligament. Dislocation can cause stretching, tearing or rupture of these ligaments.

Tendinous injuries:

• Long head of biceps brachii tendon rupture: the long head of biceps brachii tendon passes through the glenoid cavity and inserts on the bicipital tuberosity of the humerus. Dislocation can cause tendon rupture, particularly in its intra-articular portion.
• Supraspinatus tendon injuries: the supraspinatus tendon is one of the four rotator cuff tendons that stabilizes the humeral head. Dislocation can cause stretching, tearing or rupture of the supraspinatus tendon, especially if degenerative conditions pre-exist.

The severity of injuries associated with inferior shoulder dislocation varies according to several factors, including:

• Force of trauma: a more violent trauma increases the probability of severe injuries.
• Patient age: in younger patients, tissues are more elastic and resistant, while in elderly patients the risk of severe injuries is greater due to tissue fragility.
• Pre-existing conditions: the presence of pathologies such as osteoarthritis or joint laxity increases the risk of severe injuries during dislocation.

Treatment of injuries associated with inferior shoulder dislocation:

• Dislocation reduction: medical maneuver to reposition the humeral head in its natural position.
• Immobilization: the joint may be immobilized with a brace or bandage to promote healing.
• Rehabilitation: a physiotherapy program is fundamental for recovery of joint function, muscle strength and proprioception.
• Surgical intervention: in case of severe injuries, such as complex bone fractures, multiple ligament ruptures or extensive glenoid labrum lesions, surgical intervention may be necessary to repair the damage.

Prognosis and complications:

• The prognosis for complete recovery from an inferior shoulder dislocation depends on the severity of associated injuries.
• In general, young and healthy patients with minimal injuries tend to heal more rapidly and completely compared to elderly patients or those with more severe injuries.
• Some potential complications include:
  • Joint instability and risk of future dislocations
  • Chronic pain
  • Joint stiffness
  • Muscle weakness
  • Post-traumatic osteoarthritis

Prevention:

• Avoid activities that increase the risk of shoulder trauma, such as contact sports or falls.
• Maintain good muscle strength and flexibility in the shoulder and trunk.
• Use adequate protection during sports activities.

Further reading and useful guides

“Shoulder Dislocation” – Johns Hopkins Medicine: https://www.mayoclinic.org/diseases-conditions/dislocated-shoulder/symptoms-causes/syc-20371715

• Home physiotherapy for shoulder dislocation: https://www.youtube.com/watch?v=WPveYbthxmQ – Video tutorial with physiotherapy exercises to perform at home for recovery after shoulder dislocation.
• Shoulder dislocation: how reduction occurs: https://www.youtube.com/watch?v=QukQnXldH2w – Animated explanation of how the reduction maneuver occurs to reposition the humeral head after shoulder dislocation.
• Exercises for rehabilitation after shoulder dislocation: https://m.youtube.com/watch?v=PGN0VSog4HU – Physiotherapy exercises to perform under the guidance of a physical therapist for recovery after shoulder dislocation.

Complete guide: Shoulder Pain: Causes, Diagnosis and Treatments

Complete guide: Shoulder Pain: Causes, Diagnosis and Treatments

Recommended Nutritional Support

The following products are commonly used in rehabilitation programmes to support muscle and joint health. This content is for informational purposes only and does not replace medical advice. Links are Amazon affiliates: purchasing through these links supports myphysiohelp.it at no extra cost to you.

Vegan Omega-3 from Algal Oil (paid link) — DHA and EPA from plant source. 2000 mg, 90 softgels. Gluten-free, non-GMO. Vegan-friendly.

Dolatrox — Cartilage Health Support (paid link) — Supplement in sachets for cartilage health. 30 sachets.

CartiJoint Forte — Fidia Pharmaceuticals (paid link) — 20 tablets for joint health. Gluten-free and lactose-free.

Amedial Plus — Bone &038; Cartilage Support (paid link) — 20 single-dose sachets. Hyaluronic acid and collagen for bone and cartilage health.

References

1. Zacchilli MA, Owens BD. Epidemiology of shoulder dislocations presenting to emergency departments in the United States. Journal of Bone and Joint Surgery American, 2010.
2. Kuhn JE, Blasier RB, Carpenter JE. Shoulder instability management: a systematic review of clinical practice guidelines. Journal of Shoulder and Elbow Surgery, 2013.
3. Hovelius L, Augustini BG, Fredin H, Johansson O, Norlin R, Thorling J. Primary anterior dislocation of the shoulder in young patients. A ten-year prospective study. Journal of Bone and Joint Surgery American, 1996.