January 1, 2009 Biomedical engineers developed a robotic arm to very precisely resurface the knee before replacing it. In order to do this, a 3-D image of the knee is generated, providing a live-action view of the knee during surgery. A stereo camera system constantly updates surgeons on the location of the diseased portion of the knee--this keeps the healthy parts untouched. Visual alarms and artificial resistance tell the surgeons when they are too close to healthy parts. After the resurfacing is done, the implant is placed.
More than 15 million Americans have osteoarthritis in their knees, and about 600,000 of them could be helped by a partial knee replacement. A new way to fix arthritic knees that uses robots and computers is helping patients walk out of the hospital the same day of surgery.
Once an avid runner, Harvey Saff was surprised when he was sidelined with knee osteoarthritis.
"It felt like a knife going right through me," said Saff. "That's the only description that can aptly describe it."
Saff got relief with a knee resurfacing system developed by a biomedical engineering team led by Rony Abovitz.
"What we're doing now is a stage before you'd replace an entire knee," said Abovitz, a biomedical engineer at MAKO Surgical Corp. in Fort Lauderdale, Fla. His robotic arm system makes knee resurfacing so precise, it leads to faster recovery and less pain for patients "They're walking naturally and back to work in a couple days," Abovitz said.
Here's how it works. First, a 3-D model of the knee is created to give surgeons detailed imaging. That provides a live-action view as they use the robotic arm to resurface the knee. A stereo camera system continuously updates the exact location of the diseased part of the knee, keeping healthy bone and tissue out of harm's way. If the surgeon gets too close to the "no-go zone," audio and visual alarms sound. Also, the robotic arm gives artificial resistance so the surgeon feels like he's hit a wall.
"Your hand feels like it's basically touching a real wall, and you get this sensation of being blocked," Abovitz said. After the knee is resurfaced, an implant is precisely placed. Saff couldn't believe how easy his procedure was. "I was so pain-free that they let me go the next morning," he said. Saff now speed-walks every day and can easily keep up with his three grandsons.
WHAT IS HAPTICS? Haptics is the term for incorporating touch into digital or robotic environments. It may be used to program resistance into a joystick for gaming, or to add a touch sensation to gloves used in a virtual reality simulation. This way, when manipulating a virtual object, a user is able to be certain when it collides with another object, and not forced to rely on what he or she sees. Compare what it is like to walk normally and when your foot has fallen asleep. Similar to the benefit of having full feeling in your feet, adding touch to a virtual environment makes interactions less awkward and more life-like.
WHAT ARE ROBOTS? Robots are manmade machines intended to replicate human and animal behavior. Robots are made of roughly the same components as human beings: a body structure with moveable joints; a muscle system outfitted with motors and actuators to move that body structure; a sensory system to collect information from the surrounding environment; a power source to activate the actuators and sensors; and a computer "brain" system to process sensory information and tell the muscles what to do.
The Institute of Electrical and Electronics Engineers, Inc., contributed to the information contained in the TV portion of this report.
Editor's Note: This article is not intended to provide medical advice, diagnosis or treatment.