Augmented Reality Used in Knee-Replacement Surgery in a U.S. First

Dr. Vigdorchik this week examined both patients, who are in their 50s, and reported they were doing well.

Augmented reality superimposes digital content, such as 3-D images or visual instructions, onto a user’s view of the real world through mobile devices and wearable headsets. Companies for years have been working with early versions of the technology in design, training and other areas. Increasingly, health-care providers have been expanding their use of AR for procedures that require extreme precision.

In knee surgery, the technology gives a surgeon the ability to see and follow operating plans projected onto the lens of smart glasses, allowing for more precise removal of bone and cartilage and more accurate positioning of a knee implant.

“At many time points during the operation it’s actually providing me information, making sure that my cuts are degree for degree, millimeter for millimeter, accurate,” Dr. Vigdorchik said.

The better a knee-replacement fits, the better the odds for an operation’s long-term success, Dr. Vigdorchik said.

There are roughly 800,000 inpatient knee replacement surgeries performed in the U.S. each year, according to the Department of Health and Human Services’ Agency for Healthcare Research and Quality. The U.S. represents about 50% of the global knee-replacement market, said Francesco Siccardi, chief executive of Switzerland-based Medacta International SA, which designs, makes and supplies orthopedic products.

Dr. Vigdorchik used Medacta’s NextAR augmented-reality platform for his recent surgeries. NextAR received Food and Drug Administration approval for total knee replacements in July 2020. The platform was first used in Australia last September.

In the weeks leading to the procedures, Dr. Vigdorchik took computer tomography knee scans of the patients and loaded them into Medacta’s NextAR cloud-based platform, which created 3-D models of the knees. The 3-D models are used for preoperative planning, such as deciding how much damaged bone and cartilage to remove and determining the optimal placement for an implant based on each patient’s particular anatomy.

At the start of each procedure, Dr. Vigdorchik put on a pair of augmented reality glasses. The lens of the see-through glasses, manufactured by Vuzix Corp. , include a digital display that let him view the patient’s knee and the surgical planning parameters that helped him accurately position the implants.

The display screen inside the glasses can show a 3-D model of the leg with a diagram of planned cuts. The display is interactive. If a surgeon makes cuts exactly as planned, a green line appears as instruments are moving. If cuts are off, the line turns red.

A key to any successful knee replacement is ensuring the ligaments that hold the knee in place retain their preoperative balance, or stability. For Dr. Vigdorchik’s surgeries, two quarter-size sensors attached by clamps—one above the knee joint and the other below it—were used to transmit a signal to the AR glasses with a precise measurement of their spatial position in 3-D. The data was used to help calculate the balance of the ligaments as Dr. Vigdorchik put the patients’ legs through a range of motion during surgery.

Dr. Vigdorchik said he believes augmented reality will allow for better procedures, leading to quick recoveries and better functioning of knee implants.

Tuong Huy Nguyen, a senior principal analyst at research and advisory firm Gartner, said the market for augmented reality technology will grow as the technology finds new uses.

“AR is the next generation in computing experiences,” he said. “This is how we’ll interact with the world.”

Write to John McCormick at [email protected]