What is a Dislocated Shoulder?
The shoulder is a combination of three joints coupled with tendons and muscles that allow for a wide range of motion of the arm. The shoulder is the most mobile of all the body’s joints, enabling you to perform hundreds of movements each day – sports, lifting, gardening, using a computer mouse, cooking and brushing teeth. The complex structures that allow us to make so many movements also put the shoulder at an increased risk of dislocation.
The shoulder is a ball-and-socket joint. A dislocated shoulder occurs when the humerus (upper arm bone) pops out of the glenoid (cup-shaped shoulder blade socket). A subluxation is partial dislocation of the shoulder where the head of the humerus is partially out of the glenoid socket. A complete dislocation means the bone is all the way out its socket. Both of these types of dislocations cause instability and pain.
Causes and Risk Factors
The shoulder is the most frequently dislocated joint in the body. A strong force is required to pull these bones out of place. Extreme rotation of the joint can also cause a dislocation. Some causes of shoulder dislocation include:
Falls can place a strong force on the shoulder, especially from higher heights.
Injuries incurred playing contact sports, such as hockey or football, are common causes of shoulder dislocation. Sports that involve falls, such as volleyball, gymnastics and skiing, may also cause dislocations.
Any hard blow to the shoulder, such as during a car or motorcycle accident, is a common cause of dislocation.
Seizures and electric shock. These cause severe muscle contractions that pull the shoulder out of place.
Those that are most physically active have the highest risk of shoulder dislocation. Males ages 16 to 30 fall into this group due to sustaining high-energy impacts. Older women and men are also at high risk due to falls, which are often an isolated incident.
Dislocated shoulder symptoms and signs may include:
- Severe pain
- Deformed or distorted look to shoulder
- Inability or limited ability to move the shoulder
- Muscle spasms
- Shoulder popping sound when injury occurs
- Tingling near the injury
Other complications include torn tendons and ligaments in the shoulder and nerve damage. When the shoulder is repeatedly dislocated, shoulder instability develops.
Shoulder dislocations require immediate medical attention. The doctor examines the shoulder by:
- Gently pressing and feeling around the area (palpation)
- Evaluating muscle strength
- Checking the strength of the pulse at the elbow and wrist
- Assessing response to touch
- Looking for any numbness on the outside of the upper arm
If the doctor diagnoses a dislocated shoulder, they may order an X-ray to confirm the diagnosis. Often magnetic resonance imaging (MRI) scans are ordered, which will determine any tendon or ligament injury. The doctor also needs to know how the dislocation happened and whether the shoulder has had a prior dislocation.
Types of Shoulder Dislocations
The shoulder joint can dislocate forward, backward or downward. These types of dislocations are classified as:
Anterior dislocation is the most common type of shoulder dislocation. The top of the arm bone is displaced forward out of its socket, toward the front of the body. This type may happen when the arm is put in a throwing position and then sustains a high-energy impact, as happens in many sports. Falls are also a common cause.
Posterior dislocation is rare. The top of the arm bone is displaced backwards. These dislocations can be caused by a seizure, electric shock, shoulder blow, or a fall on an outstretched arm.
Inferior dislocation is the least common type. The top of the arm bone is displaced downward and is caused by trauma that pushes the arm downward with extreme force.
In a closed reduction, the doctor will place the humerus back into the joint socket. Once the shoulder joint is back in place, pain stops almost immediately. Pain medication may also be given prior to the reduction.
A sling or brace may be required to keep the shoulder in place. This may be worn for a few days to a few weeks. Once the swelling and pain are reduced, exercises are prescribed to improve muscle strength and range of motion.
Many patients can recover successfully without surgery after a single shoulder dislocation. However, if a patient suffers from multiple dislocations or if there is more severe damage to the shoulder complex (fracture, tendon tear, severe ligament tear), surgery may be required. Recent evidence has suggested that young, extremely active patients may benefit from surgical intervention even after a single shoulder dislocation.
Generally, surgery can be performed to repair the torn ligaments and stabilize the shoulder. This is usually an outpatient, arthroscopic operation with a high success rate. More complicated situations may arise in cases of failed prior surgery or more severe bone and joint deformity in which the surgeon may recommend bone and ligament transfer surgeries.
At the beginning, rest is needed for dislocation recovery time. Lifting, any overhead activity and painful movements should be avoided. Ice may be applied for 15 to 20 minutes every couple of hours for the first few days. After swelling and pain have been reduced, a heating pad may be used for 20 minutes at a time to relax the muscles. Over-the-counter pain medications may be used until the pain has subsided.
After the pain and swelling are reduced, rehabilitation exercises are needed to help strengthen the muscles and improve the shoulder’s range of motion and may also help prevent future shoulder dislocations. Massage may also help with recovery. Physical therapy may be needed in addition to home exercises.
Though much of the shoulder strength should return within three months, it may take up to a year to regain full strength and stability. If physical therapy and home exercises are followed, complete range of motion of the shoulder should return within three months.
If you have experienced a shoulder dislocation, request an appointment with one of our shoulder and elbow specialists. We can diagnose the cause of your dislocated shoulder and suggest a treatment plan that works for you.