The Diagnosis Can be Elusive for Dislocated Shoulder

Shoulder Dislocation is extremely common-roughly half of all major joint dislocations seen in the Hospital Emergency Room are shoulder dislocations. An unstable shoulder can result from a shoulder dislocation or a shoulder subluxation, when the ball almost slides out of the socket. So an unstable shoulder is a more broad term including both dislocated shoulder and shoulder subluxation. Here is more information about unstable shoulder. Recommending the best treatment for an unstable shoulder or a shoulder dislocation really depends on many factors. To help start the conversation we present several patient case histories (real patients in my practice with all identifying information changed to ensure their privacy is fully respected).

Dislocated Shoulder Case #1:

Logan, an avid power lifter, injured his shoulder 5 years ago at age 25. He was performing a heavy bench press when he felt like his shoulder “slipped.” He had extreme difficulty dislocated shoulderperforming the bench press and military press after the injury and gradually started to have difficulty with other activities. He was initially evaluated by an orthopedic surgeon and an MRI was ordered, but he was told “there is nothing wrong.” He gradually stopped lifting weights and reduced his activities, but when the pain and discomfort persisted he sought a second opinion from another orthopedic surgeon and a diagnosis of impingement was made with a recommendation to “shave down a spur that is cutting into your rotator cuff.” Confused, Logan did some research and took a friend’s advice and scheduled an evaluation at Arizona Center for Hand to Shoulder Surgery.

Extensive Posterior Labrum Tearing

His history and examination were both highly consistent with chronic posterior instability and we recommended an MRI arthrogram to confirm the diagnosis. The MRI arthrogram confirmed extensive posterior labrum tearing that now also extended at least half way around the glenoid (socket). We reviewed our arthroscopic surgical protocol for unstable shoulder and he was extremely relieved to finally have a diagnosis and wanted to proceed with arthroscopic repair. An arthroscopic global capsular shift with labrum repair was performed and although his primary direction of injury was posterior he required a labrum repair both in the front and the back of the shoulder.

Anterior and Posterior Instability

According to one study on posterior shoulder dislocation, “more than 60% of posterior dislocations are misdiagnosed initially by the treating orthopedic surgeon, and the correct diagnosis is often delayed for months or years.” The other major point to observe is that because the shoulder is a “circle”, labels such as anterior and posterior instability are not as valid or helpful today because with the ability to evaluate and treat the entire joint using advanced arthroscopic techniques, we are learning that many different types of injuries (labrumcartilagecapsuleligamentnerve, and rotator cuff) can be part of the injury spectrum regardless of the primary direction of the shoulder dislocation. So it is vital to have a surgical technique that allows us to evaluate and treat the entire “circle” and not just a limited area of focus. This shift in thinking about shoulder dislocation has also resulted in a significant improvement in outcomes with modern arthroscopic techniques in experienced hands.

Dislocated Shoulder Case #2:

Maya, a 17 year old gymnast from Chicago, initially dislocated her shoulder doing a back flip on the balance beam 3 years ago. Since then she has had multiple episodes of subluxation and dislocation, the most recent one before evaluation at our shoulder clinic while throwing a ball. She has had multiple evaluations and extensive physical therapy over the past 3 years, but her symptoms are worsening and she has had to stop gymnastics because of the shoulder. Our examination reveals that Maya is extremely flexible both generally (double-jointed) and with examination of her other unaffected shoulder and does not have any evidence of nerve injury (sometimes seen with shoulder dislocation).

Shoulder Laxity

MRI arthrogram confirms evidence of generalized shoulder laxity and anterior inferior labrum tear. We again reviewed our protocol for unstable shoulder and global arthroscopic repair and she and her parents wanted to proceed with an arthroscopic repair. Maya was noted to have a “global” labrum tear at surgery, meaning that over time she had torn the labrum completely around the entire glenoid (socket). She also had created a chondral defect (gouge or trough) in the humeral head (ball) during one of her previous episodes of shoulder dislocation. A successful repair for Maya included not only repairing the torn labrum (cartilage) globally, but also tightening up her capsule and ligaments globally to rebalance the shoulder in all directions. This would have been impossible to do with a traditional open (incision) surgery. Modern arthroscopic techniques allow us to evaluate and treat the entire spectrum of pathology involving the entire shoulder joint.

Shoulder Arthrosis

Just as with ACL injuries in the knee, the risk of cartilage damage and further damage to the shoulder joint increases as the number of episodes of shoulder dislocation and subluxation increase. According to one study, “Patients with a history of previous shoulder dislocation were found to have a 19 times greater risk of developing severe shoulder arthrosis than patients who did not have such a history.” Another article by Brems notes that inappropriate diagnosis of the direction and degree of instability can lead to a surgical procedure that may not be ideal for a given patient’s (true) pathology. Not all instabilities are necessarily anterior or unidirectional. Even with the correct diagnosis, selection of a less optimal procedure perhaps due to surgeon preference, what Brems terms ‘‘The Standard Procedure for All,’’ may factor in the subsequent development of arthrosis. Performing the procedure on the wrong side of the joint predisposes to excessive tightness and ultimately arthritis.

Although shoulder dislocation and unstable shoulder are extremely common problems, establishing the correct or true diagnosis can often be difficult. It also follows that the recommended treatments are often highly debated and controversial. To help wade through the ocean of information and recommendations to achieve the best results for you personally, we recommend considering a second or third opinion with a shoulder specialist with significant experience utilizing the most modern techniques and treating patients with a broad spectrum of causes for unstable shoulder and shoulder dislocation.

Author
Vivek Agrawal, MD

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