Video courtesy ConforMIS
Larry Smith has undergone a total knee transplant with a twist: Its replacement was crafted courtesy of a 3-D printer.
The procedure was performed in March by Vivek Sharma of Colonial Orthopaedics. After his release, the Chester resident had a bit of stiffness and pain at home, but no major complications. Now, he can’t run, but one day recently he was down on hands and knees drilling holes and replacing a toilet and was quite comfortable, and able to get up again on his own.
As anyone of a certain age can tell you, that’s amazing of its own accord.
Smith, a 22-year U.S. Army veteran, says his knee has been problematic since he was a teen. He had surgery to deal with a bone chip on a shin bone in 1993.
“Basically, the knee just wore out,” he says.
He’d been a patient of Sharma’s for five years. Lubricant had been placed in the joint, but it was no longer helping. It was affecting his everyday mobility, from climbing stairs to just standing for prolonged periods, so Sharma suggested the replacement.
Smith described the procedure as noninvasive, even relaxing.
The replacement is a ConforMIS knee. It’s crafted by taking an image of a patient’s knee that’s used as the template for a 3-D printer to create an implant completely customized to the patient. Traditional knee replacements use implants that come in several standardized sizes and shapes.
3-D Knee ConforMIS 2
Image courtesy ConforMIS
Richmond orthopedist William E. Nordt III of OrthoVirginia, who also performs the procedure, notes that the CT scans are sent to a ConforMIS laboratory in suburban Boston where the device is printed and then shipped back in four to six weeks to the doctor performing the procedure.
Sharma performs about 100 such procedures each year. He’s been using the 3-D technology for three years now, and it accounts for about 25 percent of the procedures he performs each year.
Each implant is based on each patient’s unique anatomy, he says. It’s “nearly an exact replica of the natural knee,” he adds, so it fits better, in a more natural way.
Nordt says that the goal in a knee replacement is to make the replacement as close to the natural knee as possible, and that's what you get with this technology. He says research indicates that the way this knee works is closer to a natural knee.
"This is the future," he says. "That's exactly what they are doing with this prosthesis."
Sharma says there have been no issues regarding insurance companies refusing to pay for the procedure. He says about 90 percent of patients could be considered candidates for this procedure. Conditions such as severe bow legs or knock-knees may preclude the 3-D procedure.
It results in a more precise fit in the knee, and results in a bit faster recovery and a better range of motion than when off-the-shelf replacements are used, according to Sharma. “It feels like their own knee,” he says.
Nordt says his experiences with the ConforMIS knee have been positive, with patient recovery rates the same or slightly faster compared with traditional knee replacements, and positive midterm outcomes.
The drawback for Sharma is that there is no long-term data regarding durability and performance. Most traditional implants can be expected to last 20 years or so. He says he’s hoping the devices will last at least that long.
Nordt notes that while the 3-D process offers some slight advantages, traditional knee replacements work just fine. He expects the gap to widen, though, as the technology is refined and improves. "This is good, but by and large traditional knee replacments work great," he says.
He also cautions that pressures on providers to keep costs down mean there's little room for high-tech gadgets and procedures that offer only marginal improvements in outcomes in comparison with traditional methods.
Still, Nordt is bullish on 3-D tech in medicine. He foresees variations of 3-D printed tissue of metal or plastic or things closer to biological tissue.
"I think you're going to see it a lot," he says.
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