Shoulder Instability

The shoulder joint is a ball-and-socket joint. The “ball” is the head of the humerus (upper arm bone), and the “socket” is the glenoid part of the scapula (shoulder blade). This joint allows a wide range of motion but sacrifices some stability for mobility.

Shoulder instability is a pathological condition in which the structures surrounding the shoulder joint fail to function effectively, resulting in the head of the humerus not being able to remain in its normal position.

In mild cases, the humeral head may partially slip out of the joint (subluxation), while in more severe cases, it may completely dislocate, leading to a shoulder dislocation.

This condition can lead to pain, weakness, dislocations, or a sensation of the shoulder “giving out.”

Shoulder instability is classified into traumatic and non-traumatic (atraumatic).

Traumatic shoulder instability results from a specific injury or trauma, such as a fall on an outstretched arm or a direct blow to the shoulder. The injury usually tears or stretches the ligaments and the labrum, which are key stabilizers of the shoulder joint, leading to acute dislocation (of the glenohumeral joint). The dislocation may be anterior, posterior, or inferior, depending on the direction the humeral head moves. Anterior shoulder instability is the most common type of shoulder instability due to weakness in the joint capsule, specifically in the anterior (front) position. This weakness makes the shoulder more prone to dislocation or subluxation in this direction.

Non-traumatic (atraumatic) shoulder instability arises without a significant injury or trauma. The shoulder may dislocate or sublux (partially dislocate) with minimal or routine activities.

It is often observed in both shoulders and is usually due to generalized ligamentous laxity (loose ligaments). It tends to lead to multidirectional instability (anterior, posterior and/or inferior directions) and can be worsen with repetitive overhead activities or poor muscle control. It is common in individuals with hypermobile joints or those involved in activities requiring extensive shoulder range of motion, such as swimmers, dancers or gymnasts.

The most common symptoms include:

• Pain: It is usually felt in the front or back of the shoulder and can occur during movement or after activities, especially those involving overhead or throwing motions. It results from overstretched or torn ligaments, muscle strain, or damage to the joint capsule and labrum.
• Feeling of looseness: Also described as a sensation of the shoulder “slipping,” “giving way,” or not staying in place. This is often a sign of chronic instability, where the shoulder moves more than it should in its socket.
• Subluxation: A partial dislocation, where the ball of the shoulder (humeral head) comes partially out of the socket but goes back in on its own. It may cause a sudden sharp pain or a popping sensation, followed by aching or weakness.
• Dislocation: A complete separation of the humeral head from the glenoid socket.

This often requires medical assistance to reposition the joint (reduction). First-time dislocations often result from trauma (e.g., falls or sports injuries), while recurrent dislocations may follow from weakened stabilizing structures.

• Reduced functionality: Patients may avoid certain positions or movements (especially overhead or behind-the-back motions) out of fear of triggering instability. This may interfere with daily activities, sports, or occupational tasks.
• Weakness or Instability during Physical Activities: It is often noticed during physical activities requiring arm strength, such as lifting or throwing. The shoulder may feel like it’s not strong or secure enough to perform these actions.

Shoulder instability may be caused by:

• Injuries: Trauma-related dislocationsare the most common cause of shoulder instability. This usually occurs due to:
• Falls, especially onto an outstretched arm.
• Sports injuries, particularly in contact sports like football, rugby, or hockey.
• Accidents, such as car crashes or bike falls.

Genetic predisposition: Some people are born with looser joints. Even without trauma, these individuals may experience subluxations (partial dislocations) or a sense of the shoulder “slipping.”

Surgical procedures: Previous shoulder surgeries can increase the risk of instability.

Dysplasia: The abnormal development or shape of the shoulder joint components can lead to instability. Often congenital (present at birth), and symptoms may appear in adolescence or early adulthood.

Shoulder instability is typically a result of mechanical dysfunction in the joint, caused by trauma, genetics, structural issues, or prior surgeries. The shoulder’s wide range of motion makes it especially vulnerable. Treatment often depends on the underlying cause, ranging from physical therapy to surgical stabilization.

The diagnosis starts with a thorough review of the patient’s medical history. The doctor will ask about any previous shoulder injuries or trauma that might have triggered the instability. The medical history also includes any symptoms such as pain, weakness, or feelings that the shoulder might “give way” or dislocate. Additionally, the doctor checks for systemic conditions like connective tissue disorders (e.g., Ehlers-Danlos syndrome) that can cause generalized ligament laxity, making the shoulder more prone to instability.

Through a clinical examination, the orthopedic surgeon assesses the degree and direction of the shoulder instability.

While the clinical exam gives much information, imaging helps confirm the diagnosis and reveals structural damage.

MRI (Magnetic Resonance Imaging):

• Provides detailed images of soft tissues such as ligaments, tendons, cartilage, and the labrum (the cartilage rim around the shoulder socket).
• Useful for identifying tears or damage that contribute to instability.

CT Scan (Computed Tomography):

• Offers detailed bone imaging.
• Helps assess bone loss or fractures in the shoulder socket (glenoid) or the upper arm bone (humerus), which are important factors in recurrent instability.

The first option for the treatment of shoulder instability is the conservative (non-surgical) treatment that usually starts with physiotherapy programs. The goal is to strengthen muscles around the shoulder, particularly the rotator cuff and scapular stabilizers.

Exercises focus on improving joint stability, maintaining normal range of motion, and restoring normal shoulder mechanics. Patients are guided to perform exercises safely to allow use of the arm in daily activities.

This approach helps avoid surgery and can be effective in many cases, especially if the instability is not severe or traumatic.

If conservative treatment is ineffective and symptoms persist, surgical treatment becomes the most suitable option. Surgical treatment for traumatic shoulder instability is typically performed arthroscopically.

During shoulder arthroscopy, the surgeon inspects the ligaments, labrum, capsule, and other soft tissues for damage. The damaged structures are repaired or reattached to their correct anatomical locations. This minimally invasive technique leads to less pain, quicker recovery, and fewer complications compared to open surgery. Shoulder arthroscopy aims to restore the shoulder’s stability and prevent future dislocations.

Dr. Panagiotis Pantos is a specialist in upper limb orthopedic surgery with extensive experience in shoulder instability. He offers personalized treatment plans tailored to the specific needs of each patient, ensuring a careful and responsible approach to care.

Contact the doctor to schedule an appointment and learn more about how he can give you a safe and effective solution to your problem.

What happens if shoulder instability is left untreated?

Shoulder instability, if left untreated, can lead to the following consequences:

• Increased Frequency and Severity of Pain:Without proper treatment, the shoulder may continue to slip or partially dislocate, causing recurring pain. Each episode can damage the joint further, leading to more intense and chronic pain over time.
• Restricted Range of Motion:The shoulder joint may become stiff and less flexible.  Simple activities like reaching overhead, dressing, or lifting objects can become difficult. Scar tissue or inflammation can develop, further limiting movement.

Prompt diagnosis and treatment by an experienced orthopedic specialist are crucial to avoid these long-term complications.

Delaying treatment may allow the instability to worsen, possibly requiring open surgery (a more invasive procedure) to repair or tighten the shoulder ligaments and structures.

Surgery recovery can be longer and more complicated than early non-surgical management.

How soon can I return to my daily activities after an arthroscopic surgery for shoulder instability?
The recovery time after an arthroscopic surgery for shoulder instability varies widely based on the extent of the procedure and the patient’s overall health. Generally, recovery from surgery and a return to normal daily activities can range from a few days to several weeks, depending on the specific procedure, the patient’s healing process and the surgeon’s specific recommendations. Effective cooperation between a patient and physiotherapist is crucial for achieving optimal results. This collaboration involves open communication, active participation in treatment plans, and a shared understanding of goals.  

Is there a possibility of shoulder instability recurrence after surgery?

The likelihood of recurrence depends on the type and severity of the shoulder instability. The success of surgery largely depends on the procedure used (e.g., arthroscopic repair vs. open surgery), the surgeon’s experience, and how well the damaged tissues are repaired or reconstructed.

The surgical technique and quality as well as the patient’s adherence to post-operative guidelines from the doctor and physiotherapist significantly affect the success of recovery and risk of recurrence.

Following the surgeon’s and physiotherapist’s post-op instructions — such as immobilization period, gradual return to movement, and avoiding risky positions early on — is critical. Non-compliance can increase the risk of re-injury.

Structured rehabilitation focuses on restoring range of motion, strengthening the rotator cuff muscles, and improving proprioception (body awareness) of the shoulder joint. This enhances joint stability and reduces recurrence.

How important is the surgeon’s specialization for arthroscopic shoulder instability treatment?

A surgeon’s specialization is significant for arthroscopic shoulder instability treatment. Shoulder arthroscopy is a technically demanding procedure and requires specialized training and experience. Arthroscopic procedures, especially on the shoulder, require precise skills because the shoulder is a complex joint with many small structures. Specialized orthopedic surgeons have specific training to navigate this complex. Specialists are better equipped to identify the exact type and extent of instability (e.g., how much the ligaments or labrum are damaged), which is critical for tailoring the right surgical technique. Different types of shoulder instability may require different arthroscopic repairs or reconstructions. Surgeons with focused experience know the best approach to restore stability. Experienced specialists are more likely to achieve successful repairs, leading to fewer complications such as infections or nerve injuries. Proper treatment reduces the chance that the shoulder will become unstable again after surgery.

Choosing a surgeon who specializes in arthroscopic shoulder surgery increases the likelihood of a precise diagnosis, an appropriate surgical plan, and a successful, durable outcome. This expertise minimizes risks and helps patients regain shoulder function effectively.