Breakthrough rotator cuff treatment rebuilds and protects shoulder muscle from reinjury
[Apr. 17, 2023: JJ Shavit, The Brighter Side of News]
Advances in surgery have made ever better rotator cuff repairs possible. But failure rates with surgery can be high. (CREDIT: Adobe Images)
Tears of the rotator cuff are a common injury among adults. Advances in surgery have made rotator cuff repairs more effective, but failure rates are still high. However, a team of researchers from the UConn School of Medicine led by Dr. Cato Laurencin has discovered a new technique that could help repair the damaged shoulders of millions of people worldwide.
Laurencin, a surgeon, engineer, and scientist, along with graduate student Nikoo Shemshaki and other UConn Connecticut Convergence Institute researchers, has reported in the Proceedings of the National Academy of Sciences (PNAS) that a graphene/polymer matrix embedded into shoulder muscle can prevent re-tear injuries. The technique uses advanced materials to encourage muscle growth in rotator cuff muscles, addressing the real problem: 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.”
To combat this issue, the UConn team developed a polymer mesh infused with nanoplatelets of graphene. When they used it to repair the shoulders of rats who had chronic rotator cuff tears with muscle atrophy, the muscle grew back. When they tried growing muscle on the mesh in a petri dish in the lab, they found that the material seemed to encourage the growth of myotubes, precursors of muscle, and discourage the formation of fat.
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“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 focusing on studying the matrix in a large animal and looking forward to developing the technology in humans. If successful, this could be a game-changer for millions of people suffering from rotator cuff injuries.
Rotator cuff tears are a common injury that can cause significant pain and disability, affecting millions of people worldwide. The rotator cuff is a group of four muscles and tendons that surround the shoulder joint, helping to keep the arm bone in place. When one or more of these tendons tears, it can result in pain, weakness, and limited mobility.
A rotator cuff tear occurs when the tendons – the fibrous connective tissues that link muscles to bones in the shoulder area are stretched further away from the upper arm bone i.e. humerus, in turn triggering muscle strain,pain and discomfort. This happens because the shoulder is essentially a ball and socket joint that requires the muscles, bones and tendons to remain within the region of motion. There are two types of rotator cuff tears – partial and complete. In a partial tear, the tendon is torn away only to some extent and a fragment of tissue still remains affixed to the upper arm bone. A complete tear happens when the tendon detaches entirely from the humerus. (CREDIT: Creative Commons)
Traditionally, rotator cuff tears have been treated with surgery, but the success rates have been variable. Surgeons aim to reattach the torn tendon to the bone, but this can be challenging when the muscle has degenerated and accumulated fat.
Dr. Laurencin and his team's new approach to the treatment of rotator cuff tears could revolutionize the field. By focusing on muscle regeneration, rather than just reattaching the tendon, they hope to address the underlying problem and prevent re-injury.
The researchers developed a polymer mesh infused with nanoplatelets of graphene, a lightweight, strong material with excellent electrical and thermal conductivity. They then implanted the mesh into the shoulder muscle of rats with chronic rotator cuff tears and muscle atrophy. Over time, they observed that the muscle grew back, and the rats regained mobility and strength in their shoulders.
Dr. Cato T. Laurencin from the UConn School of Medicine
The researchers also tested the material in a petri dish, where they found that it encouraged the growth of myotubes, precursors of muscle, and discouraged the formation of fat.
While these results are promising, the researchers acknowledge that more work needs to be done. They plan to test the matrix in larger animals before moving on to human trials.
Shoulder injuries are a common problem, with rotator cuff tears being a major cause of shoulder pain and disability. According to the American Academy of Orthopaedic Surgeons, more than 2 million people in the United States seek medical treatment for rotator cuff tears each year. These injuries can occur suddenly, as a result of a fall or other trauma, or develop gradually over time due to overuse or age-related wear and tear.
Traditional treatments for rotator cuff tears include physical therapy, medication, and surgery. Surgery is often necessary to repair the torn tendon and reattach it to the bone. However, surgery is not always successful, and many patients experience re-tears or ongoing pain and weakness in the shoulder.
The new technique developed by Dr. Laurencin and his team represents a significant advance in the field of shoulder injury treatment. By targeting the underlying problem of muscle degeneration and fat accumulation, the researchers hope to improve the success rate of rotator cuff repairs and reduce the risk of re-injury.
The matrix developed by the UConn researchers is made up of a polymer mesh infused with nanoplatelets of graphene, a strong and lightweight material that has a range of potential medical applications. The matrix is designed to be implanted into the damaged muscle tissue, where it can provide support and encourage muscle growth.
To test the matrix, the researchers conducted experiments on rats with chronic rotator cuff tears and muscle atrophy. They implanted the matrix into the rats' shoulder muscles and observed how the tissue responded over time. They found that the matrix was able to promote muscle growth and discourage the accumulation of fat, resulting in improved muscle function and reduced risk of re-injury.
Encouraged by these results, the researchers plan to continue their work by testing the matrix in larger animal models, such as pigs, before moving on to human trials. They hope to refine the technique and optimize the design of the matrix to achieve even better outcomes.
The potential benefits of the new technique are significant. However, there are still many challenges to overcome before the matrix can be widely adopted as a treatment for rotator cuff tears. In addition to the need for further testing and refinement, there are also concerns about the safety and long-term effects of the matrix. Some experts have raised questions about the potential for the graphene nanoplatelets to cause inflammation or other adverse reactions in the body.
Despite these challenges, Dr. Laurencin and his team are optimistic about the potential of their new technique. They believe that by addressing the underlying problem of muscle degeneration and fat accumulation, they can significantly improve the outcomes of rotator cuff repairs and help patients recover more quickly and completely from their injuries.
Rotator cuff injury symptoms
The pain associated with a rotator cuff injury may:
Be described as a dull ache deep in the shoulder
Make it difficult to comb your hair or reach behind your back
Be accompanied by arm weakness
Some rotator cuff injuries don't cause pain.
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:
Age. The risk of a rotator cuff injury increases with age. Rotator cuff tears are most common in people older than 60.
Some occupations. Jobs that require repetitive overhead arm motions, such as carpentry or house painting, can damage the rotator cuff over time.
Certain sports. Some types of rotator cuff injuries are more common in people who participate in sports like baseball, tennis and weight-lifting.
Family history. There may be a genetic component involved with rotator cuff injuries as they appear to occur more commonly in certain families.
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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