Don Shrubshell photo

Surgeon Bus Tarbox, right, watches images from a camera inside Mitchell Smith’s knee as he performs surgery with, from left, Brenda Bohon, LPN surgical technician; Chris Parker, nurse anesthetist; and Dan Stockman, orthopedic technologist.

Research at the University of Missouri-Columbia is giving new hope to people who suffer lifelong knee pain caused by damage to a cartilage disk called the "meniscus."

KNEES UNDER THE KNIFE: Treating meniscus tears

WHO GETS MENISCUS INJURIES? This common injury is not limited to athletes; it’s seen often in older adults. Tears to the meniscus can result from a sudden twist of the knee, a deep knee bend or as a result of long-term degeneration. There are about 1 million meniscus-repair surgeries each year in the United States.

Sources: James Cook; Krames Communications

Lora Wegman graphic

Most of the nearly 1 million meniscus surgeries performed each year are the result of damage doctors consider irreparable, meaning certain arthritis and possible knee replacement in the future. That’s because the only way to treat meniscus tears has been to surgically remove the damaged portion.

But a new device developed by MU veterinarian James Cook at the University of Missouri Comparative Orthopaedic Laboratory and given recent Food and Drug Administration approval allows surgeons to arthroscopically induce healing in places that previously had to be removed.

"It’s really frustrating for surgeons because technically, surgically they can repair them all," Cook said of injuries to the meniscus. "But even the best repair in the majority of these problems won’t heal because … the majority of the meniscus has no blood supply, and for healing to occur, you need blood supply, and you need cells."

Cook said the new device, known as the BioDuct Meniscal Fixation Device, brings blood to the bloodless portion "long enough to win the race and then go away."

The meniscus is a crescent-shaped cartilage that acts as a shock absorber between the thigh bone and shin bone. It becomes torn when the knee twists too far or during a deep knee bend, especially in older adults.

"It’s not just the elite athletes; it’s actually more common in the weekend-warrior type of person," Cook said, "but it’s also things like … climbing stairs or hiking."

It can happen to anybody, said Bus Tarbox, a Columbia Orthopaedic Group doctor who performs four to six knee surgeries a week in patients of all ages. "The key to Dr. Cook’s study is how to treat the knee if the tear is in the inner two-thirds of the meniscus," he said. "If we can somehow get blood into that site, it might be able to heal."

If the tear is in the outer one-third, stitches can repair the tear by squeezing it back together, Tarbox said. "The problem is only 10 to 15 percent of meniscus tears are in that area," he said.

For the rest, Tarbox said, the only option is to remove the torn portion of the meniscus. Once the "cushion" is removed, however, a debilitating wearing begins at the points where the thigh bone and shin bone are touching. In as little as three years after surgery, the articular cartilage that protects the thigh bone will be worn away, and bone will rub on bone, creating the painful condition known as arthritis. With age, Tarbox said, patients might eventually require a total knee replacement.

"There’s a bunch of guys out there with arthritis," Tarbox said. "Now, with this device, it allows us to fix tears that before we couldn’t repair."

Bioengineer Herb Schwartz, whose company invented the technique and contracted with MU for research into its implementation in dogs, likened it to "plumbing for your knee."

Use of the device in worst-case scenario meniscus tears in dogs resulted in partial repair within six weeks and more extensive healing after 12 weeks. Cook explained that the new device draws blood from the blood-rich outer meniscus to the bloodless portion via a hollow bioabsorbable screw.

"I have surgeons calling me all the time asking me when it’s going to be available," Schwartz said. "We’re working as quick as we can to get things ready." Schwartz said his company plans to market the technique itself initially but probably will sell rights to the device to a larger orthopedic company later.

"That’s great because it will get out there quickly," Cook said of a major orthopedic company owning the device.

Schwartz said that the relatively minor cost of the device is far less expensive than the eventual cost of total joint implants, making insurance companies inclined to cover its use.

Cook’s research will be published in the American Journal of Sports Medicine. Schwartz’s company, Schwartz Biomedical LLC based in Fort Wayne, Ind., paid for the research and is entitled to any profit as the inventor; MU can publish findings that help the school and Cook’s team.

"Its fun for me," said Cook, who is especially pleased because he believes the research will eventually help animals. Cook said a lot of labs use animals to develop procedures for humans, but "very few of them bring it back to … people’s pets.

"If I’m going to help that species at the end of the day," he said, "it justifies it more for me."

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