If you’ve ever experienced your shoulder feeling loose, slipping out of place, or even fully dislocating, you understand the concern and discomfort it can bring. In this post, we’ll take a closer look at shoulder instability, including its causes, symptoms, treatment options, and recovery path.

• Shoulder instability occurs when the shoulder joint’s ball moves partially (subluxation) or completely (dislocation) out of its socket.
• Common causes include trauma, repetitive motion, and sometimes genetic predisposition.
• Symptoms vary, and patients may experience pain, a sensation of the shoulder giving way, repeated dislocations, or a persistent feeling of looseness.
• Treatment options range from non-surgical approaches (pain management, physical therapy) to surgical interventions to repair damaged tissues.

The shoulder joint is designed for a remarkable range of motion. This mobility, however, comes at a price: inherent instability. Unlike the hip, which is a deep ball-and-socket joint, the shoulder is more like a golf ball resting on a tee. The “ball” is the head of the humerus (upper arm bone), and the “tee” is the shallow socket called the glenoid, part of your shoulder blade (scapula).

Because of the inherent instability of the golf ball on the golf tee, there are several structures around the shoulder that help stabilize it. Shoulder instability occurs when the structures that normally provide stability become compromised, allowing the humeral head to move excessively or even completely out of the glenoid socket. This can manifest in two primary ways: subluxation or dislocation.

Subluxation refers to a partial or incomplete dislocation, where the humeral head temporarily slips out of the glenoid and then returns to its normal position.

Dislocation, on the other hand, is a complete separation of the humeral head from the glenoid socket. This event is often accompanied by severe shoulder pain, visible deformity, and an inability to move the arm. A dislocated shoulder usually requires medical intervention to be manually repositioned, a procedure known as closed reduction.

The stability of the shoulder joint relies on a complex interplay of several anatomical structures:

• Joint Capsule: A fibrous sac that encloses the entire shoulder joint, providing a first line of defense against excessive movement.
• Ligaments: Strong, fibrous bands that reinforce the joint capsule.
• Labrum: A ring of tough, rubbery cartilage that surrounds the glenoid socket, deepening it and providing a suction cup-like effect to hold the humeral head in place.
• Rotator Cuff Muscles: A group of four muscles and their tendons that surround the shoulder joint, providing dynamic stability by actively holding the humeral head centered in the glenoid during movement.

[Galen to insert image of shoulder stabilizing structures]

When any of these stabilizing structures are damaged or weakened, the shoulder becomes prone to instability and may lead to recurrent episodes of subluxation or dislocation.

Shoulder instability can arise from a variety of factors. Traumatic injury is a common cause of shoulder instability, particularly in active individuals. A significant force, such as a fall onto an outstretched arm, a blow to the shoulder, or a sports-related injury can force the humeral head out of its socket.

For some individuals, especially athletes involved in overhead sports like baseball, swimming, or volleyball, repetitive stress on the joint can gradually stretch the ligaments and capsule over time. This can lead to a laxity in the joint, making it unstable.

Additionally, a smaller subset of the population is born with naturally loose ligaments throughout their body. For these individuals, shoulder instability can occur with minimal or even no trauma.

Finally, prior dislocation is a risk factor. Once a shoulder has dislocated, the soft tissues (capsule, ligaments, labrum) that were stretched or torn during the initial event may heal in a lengthened or compromised position. This may increase the risk of recurrent dislocations or subluxations. If multiple dislocations occur (or sometimes even after a single dislocation), the golf tee (glenoid) can begin to have bone wear away, turning it into essentially a broken golf tee. If this occurs, further dislocations even more likely. Once bone is worn away, further dislocations can happen even with minimal trauma such as sneezing or coughing.

The symptoms of shoulder instability can vary depending on the severity and frequency of the episodes, but they generally revolve around a feeling of looseness or apprehension in the shoulder. Common symptoms include pain, a sensation of the shoulder giving out, weakness, numbness or tingling, and visible deformity. Patients may also experience repeated shoulder dislocations or subluxations. 

It’s important to note that these symptoms can overlap with other shoulder conditions. A thorough medical evaluation through a combination of medical history, a physical examination, and imaging studies supports an accurate diagnosis.

Treatment options depend on factors such as the cause of instability, the severity of symptoms, the patient’s age, activity level, and whether it’s a first-time event or a recurrent problem. Options generally fall into two main categories: non-surgical management and surgical intervention.

Non-surgical treatment is often the first line of defense, especially after a first-time dislocation or for individuals with less severe instability. The primary goals are to reduce pain and swelling, restore range of motion, strengthen the surrounding muscles, and prevent future episodes.

For a shoulder dislocation, the immediate priority is to gently maneuver the humeral head back into the glenoid socket. This procedure is known as closed reduction and often immediately reduces the patient’s pain. Following reduction, the shoulder may be immobilized in a sling or brace for a period of time.

Other non-surgical treatments include ice application, nonsteroidal anti-inflammatory drugs (NSAIDs), and activity modification to help reduce swelling and pain. Additionally, physical therapy is typically a key part of treatment, aiming to strengthen and stabilize the shoulder muscles.

One of the risks of non-surgical management is that there is an increased risk for subsequent dislocations, and each additional dislocation risks damaging the structures more and wearing away more bone on the socket (golf tee). Surgical intervention may be considered when non-surgical treatments fail to provide adequate stability, in cases of recurrent dislocations, significant structural damage, or for individuals with high-demand lifestyles who require a more definitive solution.

Shoulder arthroscopy is a minimally invasive procedure and a common surgical approach for instability. Small incisions are made around the shoulder, through which a tiny camera (arthroscope) and specialized instruments are inserted.

The surgeon can then visualize the inside of the joint and repair damaged structures, such as reattaching a torn labrum or tightening a stretched joint capsule. In cases where arthroscopic repair is not feasible, open surgery may be necessary, which involves a larger incision.

The specific technique used depends on the individual patient’s anatomy and the nature of the instability. An experienced shoulder surgeon can evaluate the injury and guide the most appropriate treatment path.

The timeline and specific protocols can vary significantly based on the individual, the severity of the injury, and the type of treatment received. However, the overarching goal remains the same: to restore strength, mobility, and stability to the shoulder.

For a period of weeks after the injury, the shoulder may be immobilized in a sling to protect the area and allow for initial healing of the tissues.

Physical therapy is often a key part of recovery. It typically begins with passive range-of-motion exercises, then progresses to active range-of-motion and strengthening movements. It is important to follow the therapist’s instructions carefully to avoid overstressing the healing tissues.

Shoulder instability is a complex condition that can impact an individual’s quality of life, ranging from a nagging sensation of looseness to recurrent dislocations. Understanding the anatomy of the shoulder, the various causes of instability, and the range of symptoms is the first step toward effective management.

From conservative approaches like targeted physical therapy, activity modification, and pain management, to surgical interventions such as arthroscopic repair, the goal is to restore the shoulder’s stability and function. Rehabilitation frequently plays a pivotal role in strengthening the joint and preventing future episodes.

Shoulder subluxation is a partial dislocation where the head of the upper arm bone (humerus) partially slips out of the shoulder socket (glenoid) and then spontaneously returns to its normal position. A dislocation is a complete separation of the humeral head from the glenoid, often requiring medical intervention to put it back in place.

While some mild cases of shoulder instability, especially after a first-time subluxation, might improve with rest, immobilization, and physical therapy, chronic instability or a full dislocation often do not resolve completely without intervention.

Recovery time may vary depending on the type of surgery and individual healing factors. Generally, it involves an initial immobilization period of 4-6 weeks, followed by several months of physical therapy to regain motion and strength. Full return to strenuous activities or sports can take anywhere from 6 months to a year or more.

Physical therapy is a key component of both non-surgical and surgical treatment for shoulder instability. It focuses on strengthening the muscles surrounding the shoulder, improving range of motion, and enhancing neuromuscular control. This helps reduce the risk of future instability episodes.

Surgery may be recommended when non-surgical treatments have failed to provide adequate stability, in cases of recurrent dislocations, significant structural damage (e.g., large labral tears, bone loss), or for individuals with high-demand lifestyles (e.g., athletes) who require a more definitive solution to prevent future episodes.