Shoulder instability can affect many individuals, from professional athletes to desk workers, who experience overuse or impact injuries to the shoulder. Shoulder instability can become chronic and interfere with the activities of daily living if left untreated, so it's a good idea to see a doctor at the onset of your symptoms.

What is Shoulder Instability?

What is Shoulder Instability?

The shoulder joint is made up of a complex network of bones, ligaments, tendons, and muscles that stabilize the joint and keep it in alignment. Shoulder instability occurs with injury to these stabilizing structures. It is often the result of trauma in which the head (ball) of the upper arm bone (humerus) in the shoulder is pushed partially or entirely out of its normal alignment in the shoulder socket (glenoid). These injuries often result in permanent stretching, tearing, and loosening of the shoulder ligaments, potentially wearing away portions of the bone important to shoulder joint stability.

Types of Shoulder Instability


Of all the joints in the body, the shoulder has the greatest range of motion, which means that it can move in multiple different directions. This characteristic also makes the shoulder more vulnerable to dislocation. Patients who experience shoulder instability may have experienced one of the following underlying injuries or conditions.

  • Complete shoulder dislocation - Diagnosed when the humeral head comes fully out of alignment with the shoulder socket, which may require emergency intervention to put it back in place
  • Shoulder subluxation - Also called partial dislocation, shoulder subluxation occurs when the humeral head is partially out of the socket and often falls back into place immediately after occurring
  • Labral tear - An injury to the fibrous tissue called the labrum that helps form the bumper of tissue around the ring of the socket
  • A genetic predisposition – Having flexible joints (double jointed) and stretchy shoulder ligaments, which can result in shoulder instability

Signs & Symptoms of Shoulder Instability


The initial signs and symptoms of shoulder instability, dislocation, or subluxation may vary depending on the condition's underlying cause and the degree of injury.

When the shoulder is dislocated completely, it is very painful and may even require a medical professional to put the shoulder back in place. When the shoulder instability is a subluxation or partial dislocation, the patient may feel as if the joint is "giving way" during a specific activity, such as throwing a ball or reaching behind or overhead.

Other shoulder instability symptoms include:

  • Shoulder pain (sudden or gradual)
  • A "clunk" sound or sensation in the shoulder
  • Weakness
  • Deformity of the shoulder’s outward appearance
  • Decreased ability to move the joint
  • A feeling of looseness in the joint, often in cases of recurrent and chronic shoulder instability

What Causes Shoulder Instability?


Shoulder instability may result from a variety of causes. These include:

  • Shoulder dislocation or subluxation from an acute injury caused by a fall or collision, or from the arm being pulled overhead
  • Athletic activities, such as baseball or football, that result in overuse injuries to the ligaments and muscles in the joint. Sports that require repeated overhead motion, including tennis, volleyball, and swimming, can also contribute to shoulder instability
  • Jobs that require repeated overhead motion

Risk Factors

Risk Factors
  • Previous injury to the shoulder joint, such as dislocation or subluxation. Even after the joint is placed back in proper alignment, the supporting tissues remain stretched and more vulnerable.
  • Micro-traumas, i.e., smaller injuries that "add up" over time
  • Participation in sports that contribute to overuse, such as throwing or serving a ball, or contact injuries from football
  • Genetically determined looseness in the ligaments that help stabilize the shoulder joint 
  • Seizure disorders such as epilepsy
Get Care

Trust NewYork-Presbyterian for Shoulder Instability Care

If you have symptoms of shoulder instability, the expert orthopedic specialists at NewYork-Presbyterian can help. Working closely with primary care sports medicine physicians and rehabilitation specialists at Columbia Orthopedics, our highly experienced orthopedic surgeons offer the full range of treatment options for shoulder instability and other conditions that affect the bones and joints. Our goal is to return every patient to optimal function and mobility.