WHAT CAUSES SHOULDER INSTABILITY?

Originally Written by Dr. B. Rodney Comisar

Picture this: A tackle in football is accompanied by a shoulder injury sustained by the defender, noted with his arm limp at his side, in pain.

Shoulder instability, or a dislocation of the “ball and socket joint,” can occur as a result of such a traumatic mechanism. It is generally a “young man’s injury,” associated with collision sports like football, hockey, or wrestling, or a motor vehicle accident. The ball, or humeral head, is forcefully separated from the glenoid, which represents the socket.

At OrthoNeuro, our team of orthopedic specialists in Columbus, Ohio, provides expert diagnosis and treatment for shoulder instability. If you’re struggling with shoulder pain or weakness, we’re here to help you regain stability and function. Contact us today for more information!

What is Shoulder Instability?

Shoulder instability occurs when the structures that support the shoulder joint become too loose, causing the upper arm bone (humerus) to move out of its normal position within the shoulder socket (glenoid).

The shoulder joint is extremely mobile, with a large range of motion; it is also the most frequently dislocated large joint. The shoulder can dislocate if the arm is pulled out to the side (arm tackle in football), as well as with a direct blow to the shoulder (fall onto the side). A traumatic dislocation typically results in an anterior labral tear or Bankart lesion.

The labrum is a bumper that deepens the socket and serves as an attachment site for the ligaments and joint capsule. The torn anterior labrum displaces from the glenoid socket and leads to joint laxity; since the labrum doesn’t typically heal back in normal position, the disrupted anatomy and lax ligaments make it easier to redislocate the shoulder.

In some instances, the shoulder will “pop back in” or reduce, spontaneously or with gentle manipulation; in other cases, the dislocated shoulder remains “out” until reduced in an emergency room setting with the aid of sedation. An appropriate evaluation includes a comprehensive history and physical exam; x-rays; and frequently an MRI.

Types of Shoulder Instability

There are three main types of shoulder instability:

Traumatic Shoulder Instability – Often caused by a severe injury, such as an initial shoulder dislocation from a fall, accident, or sports-related impact.
Atraumatic Shoulder Instability – This develops gradually due to repetitive overhead motion, commonly seen in athletes like swimmers and baseball players. This type is usually related to loose ligaments.
Multidirectional Instability (MDI) – Some individuals have naturally loose joints (hypermobility), making them more prone to chronic shoulder instability in multiple directions without a specific injury.

What Causes Shoulder Instability?

Shoulder instability is usually caused by shoulder dislocation, severe injury, or trauma. The following list explains some of the common causes of shoulder instability:

Shoulder Dislocation or Severe Injury – A dislocated shoulder occurs when the upper arm bone slips out of the shoulder socket, often damaging surrounding tissues. This can lead to chronic shoulder instability if not properly treated.
Torn or Stretched Ligaments – The ligaments that hold the shoulder joint together can be stretched or torn due to repeated dislocations or excessive strain, leading to an unstable shoulder.
Weak or Imbalanced Shoulder Muscles – The rotator cuff muscles and surrounding shoulder muscles play a key role in stabilizing the joint. Weakness or imbalance can increase the risk of instability.
Repetitive Overhead Movements – Sports or jobs that require frequent overhead motions (such as baseball, swimming, or painting) can lead to shoulder injuries and loosen the stabilizing structures over time.
Genetic or Connective Tissue Disorders – Some individuals naturally have looser joints, making them more susceptible to shoulder instability without a specific injury.

What Are the Symptoms of Shoulder Instability?

Common shoulder instability symptoms include:

A feeling of the shoulder being loose or “slipping” out of place
Recurrent shoulder dislocations
Pain in the shoulder, especially with movement
Weakness in the affected arm
A clicking or popping sensation in the joint
Limited range of motion and difficulty performing overhead tasks

If you experience any of these symptoms, it’s essential to seek a professional evaluation to prevent further damage and instability.

How is Shoulder Instability Diagnosed?

At OrthoNeuro, our specialists perform a comprehensive evaluation to diagnose shoulder instability. This includes:

Medical History & Physical Exam – We assess your symptoms, past shoulder injuries, and range of motion. Our orthopedic specialists may also perform manual tests to check for excessive movement or instability in the joint.
Imaging Tests – An MRI can prove helpful in confirming the extent of the injury, including the presence of a labral tear or rotator cuff injuries.

Anterior labral tears have been demonstrated to occur between 67-100% of the time with a traumatic shoulder dislocation, highest in contact athletes. Similarly, the presence of an anterior labral tear is associated with a high recurrence rate (approaching 100% in some series) of shoulder instability in young patients returning to collision sports.

How is Shoulder Instability Treated?

Treatment for shoulder instability depends on the severity of the condition. At OrthoNeuro, we offer both non-surgical and surgical options to restore shoulder stability.

Non-Surgical Treatment

Non-surgical treatments are usually the first line of treatment for shoulder instability. Shoulder dislocations can usually be managed non-operatively. Initial treatment involves sling immobilization, pain control, and range of motion and strength recovery through home exercises and physical therapy.

Non-surgical treatments include the following:

Physical Therapy – A structured rehabilitation program strengthens the rotator cuff muscles, shoulder blade stabilizers, and shoulder muscles to improve stability and prevent future dislocations.
Activity Modification – Avoiding repetitive overhead movements and high-impact activities can help reduce stress on the shoulder joint.
Bracing – In some cases, a brace may be recommended to limit excessive movement and support the shoulder.
Anti-Inflammatory Medications – Pain relievers and anti-inflammatory medications can help manage discomfort.

Rehabilitation and bracing, in many cases, can allow for a return to sport, depending on the sport and the athlete’s position. Harnesses restrict extension, abduction, and external rotation of the arm, effectively the “dislocation position”; thus, it is easier for an offensive lineman to play in a brace compared to a defensive back. A return to sport is permitted once range of motion and strength to protect oneself has returned, understanding the associated risks of continued participation.

Surgical Treatment

If chronic shoulder instability persists despite physical therapy, surgery may be necessary. Surgery can be performed acutely for a labral tear or immediately after the season to allow for suitable recovery time prior to the ensuing season. Surgical intervention is typically arthroscopic, although, in some instances, an open surgical approach is preferable.

Common procedures include the following:

Arthroscopic Stabilization – A minimally invasive procedure that repairs the shoulder capsule and torn or stretched ligaments to restore shoulder stability.
Labral Repair – This fixes damage to the labrum, a cartilage ring that helps secure the upper arm bone in the shoulder socket.
Latarjet procedure – This procedure uses an allograft to restore the bone of the shoulder socket.

Recovery

The rehabilitation period may range from 4 months in certain athletes up to 6 months for collision sports and 8 months or more if involving the dominant arm in the throwing athlete.

Get Expert Shoulder Care at OrthoNeuro

If you’re experiencing shoulder instability symptoms, don’t wait until the condition worsens. At OrthoNeuro, our orthopedic specialists in Columbus, OH, provide expert diagnosis, physical therapy, and advanced treatment options to help you regain a stable and pain-free shoulder. Contact us today to schedule a consultation and start your journey to recovery!

Medically reviewed by Brian Skura, DO

Originally written by Dr. B. Rodney Comisar

Dr. B. Rodney Comisar is a board certified, fellowship-trained orthopedic surgeon who specializes in sports medicine related injuries. He has a sub-specialty certification in Sports Medicine. Dr. Comisar offers a full spectrum of sports medicine surgery, including arthroscopy and minimally invasive procedures. Dr. Comisar’s special areas of interest include: multi-ligamentous knee injuries/dislocations; ACL injuries/reconstruction; rotator cuff injuries/tears; patellar instability/dislocation; proximal hamstring ruptures; shoulder instability; and shoulder arthritis including total shoulder replacement and reverse total shoulder replacement.

Sports Injury? Schedule an appointment with Dr. Comisar today! Call his direct line at 614-839-2108 or click the button below to request an appointment online.

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