When Dr. Wallace Huff read about a new technology that allowed knees to be surgically replaced with a customized joint, the Lexington orthopedic surgeon was intrigued.
Up until then, replacement knees had only been available off the shelf, in varying sizes that sometimes didn’t quite match the patient’s anatomy.
“I am always on a quest for perfection, like most surgeons are,” Huff said. “Eighty to 85 percent of patients who have traditional knee replacement are happy with them, but I felt like we could do better.”
Huff began studying the literature on the new FDA-approved procedure and was particularly struck by the fact that people who had had both knees replaced, one using the traditional off -the-shelf replacement and one using the new customized knee, preferred the later. He said the customized knee felt “more normal” to them.
He also had noted that even when he performed a traditional total knee replacement where everything had gone smoothly, patients still sometimes reported feeling residual pain.
“The number of people saying that now is much smaller,” said Huff, who has been doing the new procedure for four years.
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Dr. Wallace Huff
Huff attributes the procedure’s success to the CAD technology that allowed customized knees to be a feasible option. Replacing knees with customized joints was cost prohibitive until CAD engineers found a way to convert a CT scan of the knee to a 3D model. Huff described the imaging software as user friendly, allowing the technology to be marketed to surgeons on a wide scale.
The company that produced the software, ConforMIS, also manufactures the replacement joints and the instruments used to perform the surgery.
“It’s one tray of instruments versus eight pans of instruments that have to be prepped and sterilized,” Huff said. “It’s definitely more efficient, and I’d guess a cost savings to the system.”
With the technology having been developed in the past several years, the longevity of the customized knee replacement remains to be seen, but Huff said he is hoping for a 20- to 30-year window. The current off -the-shelf knee replacements usually last between 10 and 20 years.
“With the CT scan providing cutting guides and the customized fi t of the knee, there should be less wear over time,” Huff said.
Because much less bone is being resected due to the exact nature of the cuts, Huff said the surgery can be done on an outpatient basis with a long-lasting local anesthetic, and the recovery is also shorter. The complication rate is also lower, he said, especially infection rates.
The surgery itself takes an hour, and Huff describes it as a very step-by-step operation.
“You already have the blueprint laid out, knowing beforehand exactly what we’ll remove and the angles of the cuts,” he said. “There’s no guesswork, and it decreases the human error component, particularly when it comes to proper alignment.”
Huff said he is surprised more orthopedic surgeons aren’t using the procedure.
“A lot of times, surgeons get comfortable with the way they are doing things,” he said.
Also the customized knee replacement is geared toward patients who don’t have other issues compounding the knee replacement surgery, such as a structural abnormality. It also takes six weeks for the knee to be mapped, made and delivered. Another possible drawback is that some insurance companies do not cover the customized knee replacement.
“There’s still some work to be done on that front,” said Huff.
Within the past two years, the number of total joint replacement surgeries being performed has increased with the advancement of technology that has allowed for less post-surgical pain and shorter recoveries that don’t require the level of support they once did. Most of the surgeries are being performed among the 40- to 80-year-old age group, with sports injuries accounting for many of the younger patients.
Huff said he performs 200 to 250 cases a year. Nationwide, more than 600,000 knee replacements are done each year. According to the American Academy of Orthopaedic Surgeons the demand for total knee replacement surgery is expected to exceed 3 million by the year 2030 due to an aging population staying in the workforce longer and rising rates of obesity.
Fayette County resident Betty Shelton, 79, opted to have Huff perform the customized knee replacement surgery in December after suffering pain in her knee that she said doctors told her was being caused by “bone on bone.” The discomfort made it difficult for Shelton to play with her grandchildren or go the way she had always been used to growing up on a farm.
“I was walking down the hall that same day,” she said of her post-surgical recovery. “Within two weeks I didn’t need a walker or a cane.”
Since the surgery, Shelton said, she has not felt pain in the replacement knee.
“I get down on the floor with one grandchild on each leg,” she said. “It’s been so great. What amazes me is when I step off the curb it feels so natural I forget I even had it done.”