Each year over the next decade, between 1 million and 3 million patients are expected to have their knees replaced, and many will want to leave the OR with natural-feeling new joints that let them hike, bowl or get back on the tennis court as soon as possible. The exploding demand for knee replacements is good for business, but do enough surgeons have the experience needed to perform the procedures effectively? It’s a fair question to ask when you consider that, by some estimates, surgeons who do fewer than 30 knee replacements a year perform about 80% of arthroplasties.

High-tech solutions that take some of the guesswork out of performing knee replacements could level the playing field between high- and low-volume docs, but surgeons of all skill levels can benefit from working with technologies that help them place implants that perform better and last longer.

Anthony Adili, MD, FRCSC, became a bit of a pioneer earlier this year. In January, the chief orthopedic surgeon at St. Joseph’s Healthcare Hamilton in Ontario became the first surgeon in Canada to perform a robotic knee replacement.

For Dr. Adili, robotic surgery offers the opportunity for better pre-op planning and more precise cuts and implant placement. With the robotic method, a patient undergoes CT scanning to develop a 3D model of the knee. Surgeons use that model to come up with a plan for the procedure and to determine the best implant to fit a patient’s knee. Once in the OR, the surgeon and robotic arm work in tandem to cut only within the pre-planned areas. The process eliminates the estimation and manual cutting that comes with traditional knee replacement, says Dr. Adili.

“If you want 3 degrees of mechanical alignment, you’re going to get very close,” says Dr. Adili. “If you want 4 degrees of slope, you’re not guessing because of the modeling and navigation that goes with this.”

Dr. Adili says he focused on outcomes when he decided to pursue the robotic knee procedure about 3 years ago. He also had a desire to do more partial knee replacements. It’s a trickier procedure, but it comes with the opportunity to keep more of a patient’s knee intact without significantly altering its natural biomechanics.

“Partial knee replacement is harder to do because it’s technically more demanding to get the alignment right,” says Dr. Adili. “With robotic technology, more patients will have access to partial replacements instead of defaulting to total knee replacement.”

Dr. Adili points out that the precision cuts and pre-op planning associated with robotic surgery result in less soft tissue damage, smaller incisions and better joint alignment. “Longevity is highly associated with the alignment of the prosthesis,” he says. “If you have better alignment, you get better longevity.”

For too long, patients have had to settle for implants that didn’t quite fit right, says Edward Westerheide, MD. It can be like going to a shoe store and getting stuck between sizes.

“Implant manufacturers created knee replacement systems that didn’t match anyone’s particular joint,” says Dr. Westerheide of Orthopedic Specialists & Sports Medicine in Newark, Ohio. “They wanted to make one that matched most people’s anatomy.”

About 2 years ago, Dr. Westerheide began offering custom-built knee implants and using custom instruments to ensure the alignment, cutting and placement are precise. The custom implants and jigs are created from a patient’s CT scan. A software program takes the scan of the hip, knee and ankle and creates a 3D model of the knee. Then, it’s time for production. The manufacturer only needs about 6 weeks lead time to make the 3D-printed instruments and the metal implants, which are built to match the size and shape of the patient’s anatomy.

Dr. Westerheide says the added costs of the custom implants and instruments are offset by the savings in other areas. The jigs are single-use, so the instruments do not require the sterilization and reprocessing that reusable ones do. They also don’t take up space on the shelves because the system comes in a single box.

About 20% of patients who undergo traditional knee replacement have not been completely satisfied with the results, says Dr. Westerheide. The custom approach has already garnered positive feedback from Dr. Westerheide’s patients, and that’s what’s driving the change. “If 5% of patients who get knee replacement aren’t happy, that’s a very reasonable goal,” he says. “We should be able to achieve that.”

3. Better alignment

The goal for all the new knee-related technology is to achieve more precise outcomes, says David Mayman, MD, a hip and knee surgeon at Hospital for Special Surgery in New York City. “We know the traditional tools we’ve used over the last 50 years are not all that accurate,” he says.

“We’ve done OK with that technology. But it’s 2019. We can do better.”

One solution: Handheld accelerometer- and gyroscope-based instruments that can provide surgeons with alignment guidance, says Dr. Mayman. The single-use device has inertial sensors that give surgeons real-time feedback about where to cut into the femur and tibia to properly place the implant. Surgeons use the palm-sized device to get an exact reading of the proper angles (flexion, varus/valgus alignment and slope) in relation to the mechanical axis of the leg. Once they get the desired readings, surgeons pin their blocks and make their cuts.

At less than $1,000 per instrument, the device doesn’t come with the hefty capital investment that the other options do, says Dr. Mayman. They also work with any implant, which gives you flexibility.

“If you don’t do as many and don’t have that level of confidence, this gives you that level of confidence,” says Dr. Mayman. “I set the device up. These are my numbers. I know they are going to be accurate.”

Worth the investment

When it’s time to add new joint replacement technology to your ORs, consider more than the price tag. Here’s an example: A custom knee-cutting block might cost $400 to $600 more compared to the mechanical guides that surgeons have always used when cutting into bone. Should you spend more on the custom option?

“In my mind, it’s absolutely worth it,” says Ritesh R. Shah, MD, an orthopedic surgeon at Chicagoland’s Illinois Bone and Joint Institute. “It’s much more exact. It’s much less damaging to patients.”

Dr. Shah says custom cutting blocks can help him make more precise cuts, which means patients will feel better after surgery and require less physical therapy and fewer post-op pain meds. If he can show his patients are doing better after 90 days or longer, then payers will see the value in reimbursing more customized surgery.

“It’s an additional upfront cost to the facility,” he says, “but the long-term outcomes speak for themselves.” OSM