New tech gives a leg up to knee surgery
● For two years, Cape Town psychologist Lesley Nortje could not walk her dogs due to excruciating knee pain that stemmed from a decade-old injury.
Today, the 62-year-old grandmother from Hout Bay is back on her feet after becoming the first person in SA to have knee-replacement surgery using new cutting-edge technology that aids precision and reduces pain.
The computer-assisted total knee replacement, which works in a similar way to GPS navigation, uses an advanced camera and infrared beams to measure the position of the patient’s bones and the surgeon’s instruments to ensure the correct alignment of the prosthetic replacement knee.
Orthopaedic surgeon Dr Richard von Bormann, who performed the surgery at Cape Town’s Netcare Christiaan Barnard Memorial Hospital using the Brainlab knee navigation platform, said the level of precision the system offers far exceeds the ability of the naked eye.
This was important, he said, because just as bad alignment of car tyres causes wear and tear, incorrect alignment in the knee results in chronic pain and early failure.
In theatre, the surgeon traces the patient’s knee anatomy and measures ligament tensions with a mapping tool that feeds the information into a computer. Throughout the subsequent operation the computer, which uses infrared beams connected to surgical instruments, triple-checks the surgeon’s movements in real time against its 3D map.
“It’s like having Google Maps on your phone,” said Von Bormann. “You might know the way home from work, but you can use it to check if there’s any traffic jam and how are you going to get home quicker. Or you are the pilot on a plane and you know how to fly a plane, but you allow the computer to help make you more reliable.
“If I put the implant slightly out, there might still be ongoing pain. If I use the traditional methods I may be a few degrees out and not see it. The computer helps me not to mess up. It double-checks and stops me and says, ‘a bit more that way’.”
It is estimated that between 8,000 and 10,000 knee-replacement operations are performed in SA each year.
The longevity of knee prostheses depends mostly on correct alignment, soft-tissue balancing and restoring the mechanical axis of the lower limb. Only three-quarters of conventional total knee replacements are correctly aligned, meaning they are less likely to dislocate and last longer.
While it’s still early days for Nortje, she is already walking her dogs — including one named Franki who also had knee replacement surgery recently. “What I’m really looking forward to once I’m fully recovered is the freedom of going for walks in the forest with my dogs and dancing at a party,” Nortje said.
“With the help of a friend, Franki and I even managed to go to the beach, and we went into the water. It was the most liberating experience to go knee-deep into the ocean after two years of excruciating pain.”
With at least two sessions of physiotherapy every week and daily exercises, Nortje has started driving herself to work and can walk short distances without crutches.
She said the surgery had also given her a chance to enjoy her two new grandchildren. “I can’t wait to play and run after them when they reach that stage of getting busy.”