Shoulder Instability

Shoulder instability can be a painful and disabling condition that affects a person’s ability to use their shoulder properly. It occurs when the supporting and stabilizing tissues fail to hold the head of the upper arm bone (the ball) in its socket. This may be due to stretched, torn, or detached tissues, which allow the head of the upper arm bone to move completely or partially out of its socket. Shoulder instability can be due to an acute injury consisting of a dislocation, subluxation (partial dislocation), or chronic injury resulting in laxity of the supporting structures.

Shoulder instability can be classified into two main types: anterior and posterior.

Anterior instability occurs when the humerus is dislocated from the front of the shoulder joint. This type of instability is most common and is often the result of a force directed to the front of the arm during sports or other physical activities that involve repetitive overhead movements of the arm.  This type of injury is also common after a fall onto an outstretched arm. Young, active athletes, particularly those participating in contact sports, are at high risk.

Posterior instability occurs when the humerus is dislocated due to a traumatic force from the back of the arm and can also be caused by direct trauma to the front of the shoulder or by repetitive strain. Unlike anterior shoulder instability, posterior shoulder instability may be more likely to present as vague posterior shoulder pain, rather than dislocations or subluxations.

Shoulder instability can be caused by a variety of factors, including:

• Trauma: A fall or direct blow to the shoulder can cause the shoulder joint to dislocate.
• Overuse: Repetitive overhead movements, such as those performed in sports like baseball, tennis, or swimming, can cause damage to the ligaments that hold the shoulder joint in place and cause instability.
• Genetics: Some people may be born with loose ligaments or shallow shoulder sockets, which can increase the risk of shoulder instability.
• Aging: As we age, the ligaments and muscles around the shoulder joint may weaken, making the joint more prone to instability.

The symptoms of shoulder instability can vary depending on the severity of the condition and type of instability. Common symptoms include:

• Pain: A sharp or aching pain in the shoulder, especially when lifting or reaching overhead.
• Weakness: A feeling of weakness or instability in the shoulder, or a sensation that the shoulder gives way, can make lifting objects or performing certain movements difficult.
• Apprehension: Certain arm positions can give the patient a feeling that the shoulder will pop out of place.
• Popping or clicking: A popping or clicking sensation in the shoulder joint during movement.
• Numbness or tingling: Numbness or tingling in the arm or hand may indicate nerve damage.
• Dislocation: In severe cases, the humerus may become completely dislocated from the shoulder socket, causing extreme pain and difficulty moving the arm.

Shoulder surgeon Dr. Daniel Kaplan will inquire about your symptoms, any incidents of trauma to the shoulder and sports participation, the onset and duration of pain, and any previous injuries, dislocations, or surgeries. He will evaluate the shoulder for signs of instability, such as excessive movement or looseness in the joint, and perform specific tests on physical exam to assess the joint’s stability.

Dr. Kaplan will order X-rays and potentially an MRI and/or CT scans to assess the condition of the bones, ligaments, and muscles of the shoulder joint. These imaging tests can help identify any structural abnormalities or damage to the joint.

With the information he has gathered, he will make his diagnosis and assessment of the severity of the instability. Then, he will develop an appropriate treatment plan. This may involve non-surgical treatments, including rest, physical therapy, medications, or surgical interventions, such as arthroscopic surgery or open surgery to repair damaged ligaments to stabilize the joint.