Engineers Tackle Rotator Cuff Repair

Rotator cuff tears are among the most common orthopedic injuries suffered by adults in the United States, according to a report in Medical Press. The culprit? Wear and tear and the effects of age.

Using a five-year $3.1 million grant from the National Institutes of Health (NIH) researchers in orthopedics have joined together with engineers at Washington University, St. Louis, Missouri, to study the way tendons attach to bones. They believe that further understanding of this connection could lead to the engineering of new tissues to enhance cuff repair.

Medical Press quoted Guy Genin, Ph.D, professor of mechanical engineering, as saying, “Every motion you make is related to the attachment of tendon to bone. The muscle is attached to the tendon, and the tendon is attached to the bone. Any break in the linkage will prevent motion, so this attachment is vital to the way the body works.”

Four tendons connect the large arm bone muscles to the shoulder. Surgeons repair tears in the cuff by suturing the tendon directly to the bone. This does not always work well. “The natural attachment system is not regenerated during healing, even following surgical repair, ” noted Stavros Thomopoulos, Ph.D., associate professor of orthopedic surgery in the School of Medicine. “The healing process leads to scar-tissue formation at the tendon-to-bone interface, and the resulting attachment is prone to re-injury.”

The two men are leading an interdisciplinary group that is trying to better understand the tendon-to-bone attachment and figure out what goes wrong in the healing process following surgery. “When material is structured like tendon and bone, mechanisms for smooth attachment and transfer of stress are harder to design, ” Genin told Medical Press. “Nature has a great design and surgical repair techniques might be improved by better understanding this. We need engineering approaches to determine what’s important.”