Knee arthroplasty: a personalised approach

Posted on 1 June 2022

Mediclinic Bloemfontein introduces ROSA, a new robotic surgical assistant that enhances total knee replacement surgery.

The cutting-edge ROSA robotic system uses real-time information and assists surgeons with precise placement of knee implants based on a patient’s unique knee anatomy. After rigorous pre-training and certification, leading orthopaedic surgeons Dr Allan van Zyl, Dr Riaan Steyn and Dr Johan van der Merwe performed the first ROSA robotic-assisted knee replacement at Mediclinic Bloemfontein in February 2022.

As Dr van Zyl explains, robotic assistance does not replace a surgeon’s skill and experience, it merely enhances it. The system provides real-time data throughout the procedure to ensure accuracy. The surgeon then guides the robotic arm accordingly. “The robot does not perform the surgery,” he assures. “It simply assists us with live data and guidance throughout the procedure. In essence, we do the surgery on a computerised simulation first – and then perform the procedure on the patient.”

The introduction of ROSA technique allows surgeons to plan their procedures even better than before. “In the past, we used X-rays to plan our surgery,” Dr Steyn explains. “Now we can create a computerised 3-D morph of the patient’s individual knee, allowing for precise bone resection and alignment during surgery. We’re able to view the knee from different angles and to make our cuts accordingly, preserving as much healthy bone as possible.”

Damaged surfaces

Total knee replacement is an operation to replace damaged knee surfaces. This damage is caused mostly by osteoarthritis, a degenerative condition that results in the loss of joint cartilage (the cushioning between the bones). It usually presents as pain, inflammation and swelling.

“Generally arthritis occurs for no known reason, although sometimes a genetic reason is apparent,” Dr van der Merwe says. “Old sports injuries can lead to arthritis and South Africa’s massive increase in obesity rates certainly contributes to arthritis in the knees,” he adds. “Arthritis has certain hallmarks on X-rays and we generally see patients when they’re experiencing the end stage of this condition.”

The patient may present with  subchondral cysts (in the bone underneath the cartilage) and osteophytes (bony protrusions) where the body is trying to broaden the weight-bearing area. Joints also stiffen to limit movement that causes pain.

Precise implant fit

“Knee replacement is normally indicated when conservative treatment for arthritis, such as painkillers and anti-inflammatories are no longer working,” Dr van Zyl says. “When a patient experiences night pain that affects sleep, and results in loss of mobility, instability and/or a necessity for crutches, we will recommend surgery.” There’s a common misconception that replacement of the entire knee is involved, when in fact the knee is fitted only with a new surface during the procedure.

The first knee replacements involved a rudimentary, one-size-fits-all hinge prosthesis. “Over time there were improvements, with small, medium, and large sizes becoming available. But with limited instruments, we still had to eyeball bone cuts to fit a prosthesis as successfully as possible,’ Dr Steyn says. “Nowadays we now have many surgical instruments and a wider selection of varying sizes and widths of implants, with additional ROSA robotics at our disposal.”

During surgery, the ROSA uses a camera and optical trackers (sensors) to identify the knee’s exact location. If the leg moves fractionally, the robot adjusts accordingly. The data assists with complex decision-making and enables Dr van der Merwe  to achieve a precise knee implant fit. This is critical to a patient’s comfort and recovery following knee replacement surgery.

“Wonderful” patient experience

Annalize Doubell, 69, recently underwent a ROSA knee replacement at Mediclinic Bloemfontein. Although now a retiree, she says she’s experienced lifelong pain and various surgeries following a car accident in her youth. Her passion for gardening also contributed to ongoing knee problems. “Although I was a bit nervous beforehand, my operation was a wonderful experience,” she says. “I was able to move my knee the same afternoon. Within just three weeks I was walking without crutches and had 90% movement in my knee.”

Having performed more than 12 ROSA procedures per month since acquiring the system, Dr van Zyl confirms that his patients are definitely seeing an easier rehabilitation process. “Patients are reporting less discomfort, easier movement and a sense of better balance in their knee very soon after surgery,” he says. “They’re also reporting lower usage of pain relief medication, fewer physiotherapy sessions and overall improved knee function following surgery.”

The ROSA has also been linked to shorter hospital stays and lower rates of hospital readmission compared to traditional surgical techniques.

• The ROSA technique is also available at Mediclinic Stellenbosch, Mediclinic Durbanville, Mediclinic Gariep and Mediclinic Kimberley.