ConforMIS News

  • Sonntag, 3/23/14

    Custom-made implants offer new possibilities in joint-replacement surgery (Columbia Daily Tribune)

    Knee pain had always been an issue for Irene Sackreiter.

    „I’ve always been knock-kneed. When you have a misalignment, there is unusual wear and tear on one side of the joint, or arthritis sets in. There’s soft-tissue tear and trauma. It’s just like a snowballing thing,“ Sackreiter said.

    Five years ago, Sackreiter had one of her knee joints replaced. Recovery wasn’t easy.

    „The surgery is truly barbaric. During the early rehab, the pain is just so tremendous, and that’s why the patient has to be on these incredible narcotics just to do rehab,“ Sackreiter said.

    It’s understandable, then, that Sackreiter would be reluctant to have her other knee joint replaced after it started causing her discomfort. But when the pain became so unbearable that she couldn’t sleep, she scheduled a visit with an orthopedic surgeon to discuss her options. She then scheduled a „second-opinion“ appointment with Sonny Bal, an orthopedic surgeon specializing in hip and knee replacement at University of Missouri Health Care. Bal told her about ConforMIS, a company that uses digital imaging and 3-D models to create custom joint implants.

    For Sackreiter, the idea of a just-for-her knee joint was appealing.

    „There’s no way a mechanical apparatus can feel like the one you were born with,“ Sackreiter said. „The off-the-rack knee, it clicks sometimes. It pops sometimes. It doesn’t hurt, but it’s a mechanical thing.“

    Bal said it makes sense that what he refers to as an „off-the-shelf implant“ wouldn’t be a perfect fit.

    „Those designs are at least 30 to 40 years old now. They are based off anatomical information obtained from cadavers and also radiographs of the general population,“ Bal said.

    Like so many other things, „general population“ means Caucasian male.

    This is problematic, Bal said, because women have different contours to their knees than do men, and race also can factor into knee shape.

    „Asians, for example, have a knee that is bigger front to back and smaller side to side. African-Americans have a different shape to their knee,“ Bal said. „… As the diversity of our population increases, particularly in a cosmopolitan population like Columbia, most operations are compromised.“

    What’s more, biomechanics is a complicated matter influenced not only by what’s happening with the knee itself, but also with the hip and ankle. So, Bal said, surgeons must make allowances for the patient’s other structural idiosyncrasies. This might mean removing some of the patient’s bone to make the leg fit around the new joint.

    Custom implants, however, can eliminate these limitations.

    After a patient and his or her doctor have decided that a knee replacement is the best bet, image technicians take CT scans that show the critical angles of the patient’s hip, knee and ankle. These images then are transmitted to software engineers at ConforMIS, who translate those variables to create a model of the patient’s bones, as well as the knee-joint implant and the tools that will be used to perform the surgery on the patient. They use the model to test the implant and the instruments before shipping it to the surgeon.

    Click here to read the full article on ColumbiaTribune.com

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