Breakthrough rotator cuff therapy repairs and protects shoulders from reinjury

Rotator cuff tears are a common injury among adults, often resulting in pain and limited mobility. Despite surgical advancements, failure rates remain high. A new technique discovered by Dr. Cato Laurencin and his team at UConn School of Medicine aims to enhance shoulder repair for millions worldwide.

Dr. Laurencin, along with graduate student Nikoo Shemshaki and researchers from the UConn Connecticut Convergence Institute, published their findings in the Proceedings of the National Academy of Sciences (PNAS). Their innovative method uses a graphene/polymer matrix to prevent re-tear injuries by embedding it into shoulder muscle, stimulating muscle growth and addressing muscle degeneration and fat accumulation.

"Most repairs focus on the tendon," Laurencin explains, "and how to reattach it to the bone most effectively. But the real problem is that the muscle degenerates and accumulates fat. With a tear, the muscle shrinks, and the body grows fat in that area instead. When the tendon and muscle are finally reattached surgically to the shoulder bone, the weakened muscle can’t handle normal stresses, and the area can be re-injured again."

A rotator cuff tear happens when tendons, which connect muscles to bones, stretch away from the upper arm bone. To tackle this issue, the UConn team developed a polymer mesh infused with graphene nanoplatelets. When used to repair the shoulders of rats with chronic rotator cuff tears and muscle atrophy, the muscle regrew. In lab tests, the material encouraged the growth of myotubes, precursors of muscle, and discouraged fat formation.

"This is really a potential breakthrough treatment for tears of the rotator cuff. It addresses the real problem: muscle degeneration and fat accumulation," Laurencin says.

The researchers are now studying the matrix in larger animals and hope to develop the technology for human use, which could be transformative for millions with rotator cuff injuries. Rotator cuff tears, which affect millions globally, can cause significant pain and disability. The rotator cuff comprises four muscles and tendons surrounding the shoulder joint, helping keep the arm bone in place. When one or more tendons tear, it results in pain, weakness, and limited mobility.

Traditionally, rotator cuff tears are treated with surgery, which has variable success rates. Surgeons aim to reattach the torn tendon to the bone, but muscle degeneration and fat accumulation make this challenging. Dr. Laurencin and his team's approach focuses on muscle regeneration rather than just reattaching the tendon, addressing the underlying problem and preventing re-injury.

The polymer mesh infused with graphene nanoplatelets is a lightweight, strong material with excellent electrical and thermal conductivity. When implanted into the shoulder muscle of rats with chronic rotator cuff tears, the muscle regrew, and the rats regained mobility and strength. Lab tests showed the material encouraged myotube growth and discouraged fat formation.

While these results are promising, the researchers acknowledge more work is needed. They plan to test the matrix in larger animals before moving on to human trials. Shoulder injuries, particularly rotator cuff tears, are a major cause of shoulder pain and disability.

According to the American Academy of Orthopaedic Surgeons, over 2 million people in the U.S. seek treatment for rotator cuff tears annually. These injuries can occur suddenly due to trauma or develop gradually from overuse or age-related wear and tear.

Traditional treatments include physical therapy, medication, and surgery. Surgery often aims to repair the torn tendon and reattach it to the bone. However, many patients experience re-tears or ongoing pain and weakness. The new technique developed by Dr. Laurencin's team represents a significant advance by targeting muscle degeneration and fat accumulation. The researchers hope to improve the success rate of repairs and reduce re-injury risks.

The matrix, made of a polymer mesh with graphene nanoplatelets, is designed to be implanted into damaged muscle tissue, providing support and encouraging muscle growth. Tests on rats showed that the matrix promoted muscle growth and discouraged fat accumulation, resulting in improved muscle function and reduced re-injury risk.

Encouraged by these results, the researchers plan to continue their work by testing the matrix in larger animal models before human trials. They aim to refine the technique and optimize the matrix design for better outcomes. While the potential benefits are significant, challenges remain, including further testing and concerns about safety and long-term effects.

Despite these challenges, Dr. Laurencin and his team are optimistic, believing their technique can significantly improve rotator cuff repair outcomes and help patients recover more quickly and completely from injuries.

The pain associated with a rotator cuff injury may:

Rotator cuff injuries are most often caused by progressive wear and tear of the tendon tissue over time. Repetitive overhead activity or prolonged bouts of heavy lifting can irritate or damage the tendon. The rotator cuff can also be injured in a single incident during falls or accidents.

The following factors may increase the risk of having a rotator cuff injury:

Without treatment, rotator cuff problems may lead to permanent loss of motion or weakness of the shoulder joint.

This work was funded by NIH National Institute of Arthritis and Musculoskeletal and Skin Diseases Grant No. DP1AR068147 and National Science Foundation Emerging Frontiers in Research and Innovation Grant No. 1332329.



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