Dislocated Shoulder - Causes, Symptoms and Treatment

What is a Dislocated Shoulder?

A dislocated shoulder occurs when the upper arm bones (humerus) pop out of the shoulder socket (glenoid cavity) due to trauma or injury. Shoulder dislocations are the most common major joint dislocation, accounting for up to 50% of all cases. The most common type of shoulder dislocation is anterior, which occurs in as many as 97% of cases.

The shoulder is a complex joint with a wide range of motion, consisting of three bones – the humerus, the scapula (shoulder blade), and the clavicle (collarbone). The humerus fits into the shallow, cup-shaped glenoid cavity of the scapula, forming the glenohumeral joint., which is surrounded by a network of ligaments, tendons, and muscles. These structures provide support and stability to the joint while allowing for flexibility and movement in various directions.

When a shoulder gets dislocated, the humerus is forced out of its normal position within the glenoid cavity, often causing severe pain, swelling, and limited range of motion. Dislocations can be either partial, where the humerus partially slips out of the socket, or complete, where it completely comes out of the socket. In addition to trauma, dislocation of the shoulder also results from repetitive overuse, such as in athletes who engage in overhead activities such as swimming or throwing, or individuals with laxity in the ligaments supporting the shoulder joint.

Causes of a Dislocated Shoulder

Dislocated shoulders typically occur due to sudden impact or force applied to the shoulder joint, causing the humerus to pop out of its socket. Common causes include:

• Trauma or Injury – A fall onto an outstretched arm, a direct blow to the shoulder, or a forceful impact during sports activities can result in a dislocated shoulder. High-impact sports such as football, basketball, or rugby, as well as activities like skiing or skateboarding, pose a higher risk of shoulder dislocation
• Sports Injuries – Athletes involved in contact sports or activities that require repetitive overhead motions, such as throwing or swimming, are prone to shoulder dislocations. The sudden twisting, stretching, or impact on the shoulder joint during these activities can lead to instability and dislocation of the shoulder joint.
• Accidents – Motor vehicle accidents, bicycle accidents, and other types of accidents where the shoulder experiences significant force or trauma can cause a dislocated shoulder.
• Genetic Factors – Some individuals may have a genetic predisposition to shoulder instability due to laxity in the ligaments or shallow glenoid cavity. This makes them more susceptible to shoulder dislocations even with minor trauma or overuse.
• Previous Dislocations – Once a shoulder has been dislocated, it becomes more prone to future dislocations. The soft tissue damage that may not fully heal, can result in chronic instability.

Risk factors of Shoulder Dislocation

Several risk factors can predispose individuals to shoulder dislocation, including:

• Previous Shoulder Dislocation – Individuals who have experienced a shoulder dislocation in the past are at increased risk of future dislocations due to ligament and soft tissue damage that may not fully heal, leading to shoulder instability.
• Age and Gender – Younger individuals, particularly males under the age of 30, are more prone to shoulder dislocations, often due to participation in high-impact sports or activities. However, older adults can also be at risk, often due to degenerative changes in the shoulder joint or falls.
• Loose Joints – Individuals with naturally loose or hypermobile joints, often due to genetic factors, may have increased shoulder joint laxity, making them more susceptible to dislocations, even with minor trauma or repetitive movements.
• Muscle Weakness or Imbalance – Weakness or imbalance in the muscles surrounding the shoulder joint, particularly the rotator cuff muscles, can contribute to instability and increase the likelihood of shoulder dislocations.
• Anatomical Factors – Certain anatomical variations, such as a shallow glenoid cavity or structural abnormalities in the shoulder joint, can predispose individuals to shoulder instability and dislocations.

Symptoms of a Dislocated Shoulder

The symptoms are indicative of a dislocated shoulder:

• Sudden, severe pain – A sudden intense pain in the shoulder area is a common symptom of a dislocated shoulder. The pain may be sharp and debilitating, that make it difficult to even move the affected arm.
• Swelling and Bruising – Swelling and bruising around the shoulder joint are common signs of shoulder dislocation.
• Visible Deformity – In some cases, a dislocated shoulder may cause a visible deformity or bulge in the shoulder. This may indicate that the humerus has shifted out of its normal position within the joint socket.
• Limited Range of Motion – Individuals with a dislocated shoulder often experience limited range of motion in the affected arm. They may have difficulty moving the arm or rotating it in certain directions due to pain and instability in the shoulder joint.
• Numbness or Tingling – Numbness or tingling sensations in the shoulder, arm, or hand may occur due to nerve compression or stretching associated with the dislocation.
• Weakness – The arm with dislocated shoulder may start feeling weak, making it challenging to perform simple tasks such as lifting or carrying objects. This weakness is often due to pain and instability in the shoulder joint.
• Instability – Some individuals may describe a feeling of instability or looseness in the shoulder joint following a dislocation.

Types of Dislocated Shoulder

There are three primary types of shoulder dislocation:

• Anterior Shoulder Dislocation – This is the most common type of shoulder dislocation, occurring when the humerus is forced forward out of the shoulder socket. Anterior dislocations often result from a sudden impact or force applied to the shoulder, such as a fall onto an outstretched arm or a direct blow to the front of the shoulder. Symptoms include severe pain, swelling, and limited range of motion, and the affected arm may appear internally rotated. Anterior dislocations account for approximately 95% of all shoulder dislocations.
• Posterior Shoulder Dislocation – Posterior dislocations occur when the humerus is forced backward out of the glenoid cavity. These dislocations are often caused by forceful muscle contractions, such as during seizures or electric shocks, or by direct trauma to the front of the shoulder. Posterior dislocations may be more challenging to diagnose as it causes no visible deformity in the shoulder area. But, symptoms typically include pain, restricted range of motion, and a flattened appearance of the shoulder.
• Inferior Shoulder Dislocation – Inferior dislocations, also known as luxatio erecta, occur when the humerus is displaced downward beneath the glenoid cavity.It typically results in an upward displacement of the arm. This type of dislocation is rare and typically occurs as a result of extreme hyperextension or abduction of the arm. Inferior dislocations are often associated with significant pain, swelling, and limited range of motion, and the affected arm may be visibly elevated above the head. This type of dislocation requires very quick medical intervention.

Dislocated Shoulder Treatment

A healthcare provider, specifically an orthopedic doctor diagnoses a dislocated shoulder with a physical exam. They’ll look at your shoulder and the rest of your arm for the visible signs and symptoms.

Tell your provider about any symptoms you’re experiencing and what you were doing right before you injured your shoulder.

Tests to diagnose a dislocated shoulder

Your orthopedic might need some of the following imaging tests to diagnose damage inside your body after a dislocation:

X-rays – Shoulder dislocation x-rays are often used to diagnose a dislocated shoulder. X-rays use high-energy light beams to create images of the shoulder joint’s bones. The shoulder dislocation x-rays can show if the humerus has moved out of the joint, and if so, what is the extent of the dislocation .

Magnetic resonance imaging (MRI) – MRI scans can help diagnose shoulder dislocations by revealing injured ligaments or tendons.

CT scan – A CT scan can help diagnose a shoulder dislocation by creating two-dimensional and three-dimensional images of the shoulder using x-rays and a computer program. CT scans can show bones in greater density and detail and can reveal even the minute damages to the shoulder joint.

Surgeries for Shoulder Dislocation

Common surgeries for shoulder dislocation include Bankart Repair, Capsular Shift, Arthroscopic Bandkart Repair, Latarjet Surgery, Remplissage, and Open Reduction Internal Fixation. Each of the procedure is explained below in brief:

• Bankart Repair – This surgery involves reattaching the torn ligaments or the labrum to the shoulder socket to stabilize the joint and prevent any more dislocations in the future.
• Capsular Shift or Capsulorrhaphy – Orthopedic Surgeons tighten the joint capsule and ligaments to stabilize the shoulder, typically performed arthroscopically.
• Arthroscopic Rotator Cuff Repair – Sometimes, shoulder dislocations can cause damage to the rotator cuff tendons. Surgery may be necessary to repair these tendons if they are torn.
• Latarjet – Recommended for individuals with significant bone loss in the glenoid, this surgery involves transferring a piece of bone from the coracoid process of the scapula to the front of the shoulder socket to create a bony block, preventing dislocation.
• Remplissage – Remplissage surgery is a procedure to fix a shoulder dislocation. In this surgery, doctors use tissue from the shoulder to fill in the dent caused by the dislocation. This helps prevent the shoulder from dislocating again during certain movements.
• ORIF – ORIF or Open Reduction Internal Fixation or ORIF involves realigning the bones of the shoulder joint and using hardware such as screws, plates, or wires to hold them in place.

Prevention of Dislocated Shoulder

Here are a few tips you can follow to prevent a dislocated shoulder:

• Build the muscles around the shoulder joint through exercise. This can stabilize the joint and reduce the risk of shoulder dislocation in the future.
• If you engage in physical activity or sports, it is important to use proper technique to avoid unnecessary pressure on the shoulder joint.
• While performing activities that carry a risk of shoulder injury, wear a protective gear, such as shoulder pads or braces to provide an extra layer to the shoulder joint.
• If you have shoulder that has been dislocated in the past, you can undergo a rehabilitation program to regain strength, flexibility, and stability to the joint. This reduces the risk of further dislocations.