Tag: rotator cuff tears

A Common Practice in Rotator Cuff Surgery may be Counterproductive

Photo by Jafar Ahmed on Unsplash

A common practice of shoulder surgeons may be impairing the success of rotator cuff surgery, a new study from orthopaedic scientists and biomedical engineers at Columbia University suggests.

During the surgery, surgeons often remove the bursa, a cushion-like tissue, while repairing torn tendons in the shoulder joint – but the study, which is published in Science Translational Medicine, suggests that the small tissue in fact plays a role in helping the shoulder heal.

“It is common to remove the bursa during shoulder surgery, even for the simple purpose of visualising the rotator cuff,” says Stavros Thomopoulos, PhD, the study’s senior author and the Robert E. Carroll and Jane Chace Carroll Laboratories Professor of Orthopaedic Surgery at Columbia University Vagelos College of Physicians and Surgeons.

“But we really don’t know the role of the bursa in rotator cuff disease, so we don’t know the full implications of removing it,” Thomopoulos says. “Our findings in an animal model indicate that surgeons should not remove the bursa without carefully considering the consequences.”

The challenge of rotator cuff surgery

Most damage to tendons in the rotator cuff comes from wear and tear that accumulates over years of repetitive motions. Among people over 65, about half have experienced a rotator cuff tear, which can make simple daily tasks like combing one’s hair difficult and painful.

More than 500 000 rotator cuff surgeries are performed each year in the US to repair these injuries, restore range of motion, and alleviate pain, but failure is common – ranging from one in five surgeries in young patients to as high as 94% in elderly patients with large tears.

Rotator cuff repairs usually fail because of poor healing between tendon and bone where the tendon is reattached to the bone.

Bursa: friend or foe?

The bursa is a thin, fluid-filled sac originally thought to protect the tendons by providing a cushion between the tendons and adjacent bones.

The bursa often becomes inflamed, sometimes concurrently, when underlying tendons are injured, and surgeons often remove the tissue because they suspect it is a source of shoulder inflammation and pain. But recent studies suggest the tissue may be playing other biological roles besides mechanical cushioning, including promoting healing of injuries to the tendons in the shoulder.

To explore the role of the bursa in rotator cuff disease, Thomopoulos and graduate student Brittany Marshall examined rats with repaired rotator cuff injuries, with and without bursa removal.

Bursa removal impairs uninjured tendons

After the rats underwent repair of a rotator cuff injury, the researchers measured the mechanical properties of the repaired tendon and an adjacent undamaged tendon, the quality of the underlying bone, and changes to protein and gene expression.

The researchers found that the presence of the bursa protected the undamaged tendon by maintaining its mechanical properties and protected the bone by maintaining its morphometry. When the bursa was removed, strength of the undamaged tendon deteriorated and the bone quality deteriorated.

“The loss of mechanical integrity in the uninjured tendon in the absence of the bursa was striking,” Thomopoulos says. Uninjured tendons in the shoulder frequently degenerate over time after the initial injury, and “the animal data imply that retaining the bursa may prevent or delay progression of this pathology.”

In the damaged tendon, the researchers found that the bursa promoted an inflammatory response and activated wound healing genes, but no changes were seen in the mechanical properties of the repaired tendon two months after the repair. It’s possible that differences in mechanical properties would be detected after a longer healing period, Thomopoulos says, something that the research team is currently investigating.

“Overall, what we’re seeing is a beneficial role of the bursa for rotator cuff health, in contrast with the historical view that the inflamed bursa is detrimental,” says Thomopoulos.

The researchers documented similar changes to cells and proteins in bursa samples from patients who underwent surgery to repair rotator cuff injuries, suggesting comparable processes may occur in people.

The bursa as a drug delivery depot

If the bursa is not removed, the tissue could be used to deliver drugs to the repaired tendon to improve healing.

Thomopoulos and Marshall explored this possibility by injecting corticosteroid microspheres into the bursa of their rat model after tendon injury. Steroids are often used to treat musculoskeletal injuries and reduce inflammation.

“The treatment results are somewhat preliminary and require additional timepoints and mechanical characterisation before we can draw strong conclusions,” Thomopoulos says, “but our initial data supports the idea that the bursa can be therapeutically targeted to improve rotator cuff healing.”

Source: Columbia University Irving Medical Center

Low Sex Hormone Levels Linked to Rotator Cuff Tears

Photo by Harlie Raethel on Unsplash

Patients with lower levels of sex hormones are more likely to need to undergo surgery for rotator cuff tears, suggests a study in The Journal of Bone & Joint Surgery

Sex hormone deficiencies “was associated with a significantly increased incidence of RCR within [two] independent databases,” according to the new research by Peter N. Chalmers, MD, and colleagues at University of Utah. These findings add to previous evidence that hormone levels may be a systemic factor contributing to the development of rotator cuff tears, a common condition that is a major cause of shoulder pain.

The study used health insurance data for nearly 230 000 adults under age 65 who underwent surgery to repair a torn rotator cuff from 2008 through 2017. Patients were matched for age, sex, and type of insurance to patients who did not undergo rotator cuff surgery.

Patients undergoing rotator cuff repair had an average age of 54 years, and 58% were men. Most patient characteristics were similar between those who underwent rotator cuff repair and those who did not, except tobacco use, which was more common in the surgical cohort.

Dr Chalmers and colleagues found that 27% of women and 7% of men undergoing rotator cuff surgery had diagnosed sex hormone deficiency, compared with 20% and 4% respectively in the control group. Controlling for other factors, rotator cuff repair likelihood was 48% higher in women with oestrogen deficiency and 89% higher in men with testosterone deficiency.

To confirm their findings, the researchers then accessed the Veterans Administration Genealogy database which has data on millions of individuals. Here, they found that rotator cuff repair was about 2.5 times more likely for women with oestrogen deficiency and three times more likely for men with testosterone deficiency.

This study builds on a prior study by the same research group, which demonstrated that women with mutations in an oestrogen receptor gene were more likely to develop rotator cuff disease, with higher rates of failed rotator cuff surgery.

Despite limitations such as not accounting for hormone replacement therapy, the observed association between sex hormone deficiency and rotator cuff repair strongly supports the theory that low oestrogen and testosterone levels may contribute to the development of rotator cuff tears. The researchers concluded that “Future prospective studies will be necessary to understand the relationship of sex hormones to the pathophysiology of rotator cuff disease.”

Source: EurekAlert!