Orthopaedics and Rehab

Robotic knee replacement surgery enhances precision, personalization

Orthopaedics and Rehab

Surgeon showing knee replacement implants
Robotic-assisted surgery for total knee replacement adds a new level of precision and personalization to the placement of the implants.

Almost 1 million total knee replacement surgeries were performed in the U.S. in 2021, and the annual number is projected to rise to 3.5 million by 2030, according to the American Academy of Orthopaedic Surgeons (AAOS).

A trio of lifestyle factors is contributing to the increased need for “new knees:”

  • The population is aging at a rapid rate
  • People remain active much later in life
  • And obesity affects more than 42% of Americans

All of that puts additional pressure on our knees – those hard-working, weight-bearing joints that are susceptible to normal wear and tear and the degenerative effects of osteoarthritis.

Thankfully, total knee replacement, also known as total knee arthroplasty, is considered one of the most successful procedures in modern medicine, and it has continually improved and evolved since it was first introduced more than 50 years ago.

UT Southwestern recently began offering robotic-assisted total knee replacement, a leading-edge technology that helps our orthopedic surgeons deliver the most precise and personalized approach for patients. Considering most knee replacements last 15-25 years, according to the AAOS, robotic surgery can be instrumental in relieving your pain, restoring mobility, and providing you with a new knee that fits your anatomy to a T.

How does robotic knee replacement work?

First things first, we understand that the word “robot” can conjure up a lot of different images, primarily thanks to science fiction. But rest assured your orthopedic surgeon will be performing this procedure – not some cyborg – aided by technology that will enable him or her to make highly precise adjustments.

In all total knee replacements, we remove arthritic bone and damaged cartilage and resurface the end of the femur and top of the tibia and replace them with metal components. The space between the metal is filled with a durable polyethylene, or plastic, insert to replace cartilage and cushion the new knee joint.

At UT Southwestern, we recently began using the Mako robot by Stryker Corp. to assist and enhance several key elements of the total knee replacement procedure:

robotic knee replacement preoperative plan
A 3D model of the knee. (Photos: Stryker)

1. Planning and visualization: A preoperative CT scan of your knee is loaded into the software to create a 3D model, which helps us create an exact plan for how much bone to remove and where to position the metal implants. The model appears on a monitor during the surgery, and using technology called arrays, we create constant landmarks on the femur and tibia and register the actual bone with the virtual model. Therefore, when we move and flex the leg during surgery, the landmarks stay constant, and the robot continues to “see” the leg.

The surgeon operates the robotic arm.

2. Personalized adjustments: Using the 3D software, we can make micro-adjustments to the planned bone cuts – something the naked eye couldn’t see – to achieve a perfectly balanced knee.

3. Safety and precision: The robotic arm and preoperative plan are synced up, and the arthritic portions of the bone appear as a green field on the 3D model. Guiding the robotic arm, the surgeon essentially “mows the grass” to remove arthritic bone. Haptic technology, which is highly sensitive to touch, ensures the surgeon only removes the designated area, virtually eliminating the risk of damaging healthy bone, ligaments, and other surrounding tissue.

Arthritic bone slated for removal is in green.

4. Pinpoint positioning: During the procedure, we test the implants for size, position, and rotation before making them permanent. The Mako robot provides precise coordinates for the implant and can confirm that the gaps on the inside and outside of the knee remain the same throughout the arc of motion. The result will eventually be a knee that moves seamlessly with appropriate balance.

Related reading: When is it time for a knee replacement? 3 signs to look for

Benefits of robotic knee replacement

Nationally, satisfaction rates for total knee replacement surgery are very high – about 95% – whether it’s done traditionally or robotically.

The robot adds an extra layer of personalization and precision and is especially beneficial for patients with prior knee trauma, surgeries, or deformities. Perhaps its most valuable feature is that it allows orthopedic surgeons to make micro adjustments – as little as one or two degrees – to improve implant positioning and limb alignment. The resultant precision of the saw blade also reduces the need to disturb surrounding soft tissue around the knee joint.

Our team at UT Southwestern is also working on a study to measure whether robotic knee replacement surgery has fewer complications. Because there is less trauma to surrounding tissues, muscles, and ligaments, it may reduce postoperative narcotic use and even infection rate. But it’s important to note that complication rates remain low for both traditional and robotic knee replacement surgeries.

What’s next for robotic technology?

At UT Southwestern, our team of fellowship-trained orthopedic surgeons performs more than 450 total knee replacements every year. As a high-volume center, we have spearheaded many innovations in knee surgery over the years. For example, our orthopedic team was the first in the Dallas-Fort Worth area to use knee replacement techniques specifically designed for women’s anatomy.

Robotic-arm technology is simply the next step in the evolution of this popular and potentially life-changing procedure.

We anticipate it will continue to expand into other key areas as the technology continues to evolve. And as an orthopedic oncologist, I’m excited about the robot’s potential to help us remove cancerous tumors with next-level accuracy.

Because UT Southwestern is an academic medical center, we are committed to providing our patients with access to the most advanced technology. Our goal with any knee replacement is to restore the joint so it feels natural and moves comfortably. Robotic technology is a powerful instrument to help us achieve that goal and get you back to walking comfortably for years to come.

If you or a loved one are considering total knee replacement surgery and are interested in learning more, please call 214-645-8300 or request an appointment online.