Hong Kong is at the forefront of robotic surgery in Asia. The Hong Kong Sanatorium and Hospital purchased Asia's first Robotic Interactive Orthopaedic (Rio) System, a revolutionary system used mainly for partial knee replacement.

Five hospitals in the city, one private and four public, have the da Vinci Surgical System - the most commonly used robot for MAS - according to Dr Law Wai-lun, chief of the division of colorectal surgery and director of the surgical skills centre at Queen Mary Hospital. The first da Vinci system was installed at Prince of Wales Hospital in November 2005. Queen Mary got one in 2007, and Law says it has performed more than 680 procedures. In the past year alone, 160 procedures were done.

In Hong Kong, robots are most commonly used to treat prostate, bladder, kidney, cervical, rectal and stomach cancers, and pelviureteric obstruction, says Dr Simon Hou, chief of the division of urology at Prince of Wales. But other surgeries, such as liver resections and oesophagectomies, are also more commonly performed here than elsewhere, says Dr Philip Chiu Wai-yan, director of Chinese University's Jockey Club minimally invasive surgical skills centre.

Resembling something out of , the da Vinci consists of three parts: a surgeon console to control the robot; a robot cart of four arms outfitted with surgical instruments and a camera; and a 3-D imaging system that serves as the robot's eyes.

One of the greatest advantages of robots in surgery is that they offer a full range of motion in areas that are difficult to reach with human hands, such as the pelvis. Robots don't get shaky hands or suffer from fatigue, and offer a level of precision that would be impossible for a human to achieve. The biggest downside of using a robot, however, is the lack of tactile feedback; surgeons cannot feel what is going on.

This is why the new Rio system at the Hong Kong Sanatorium and Hospital is groundbreaking: it allows the doctor to hold the robot arm and guide it through the procedure. For example, the surgeon controls the machine to drill an opening into a bone, but if the surgeon drills too deep, the machine will stop him. "The system we're using incorporates technology called the Haptic Robotic System, which means that there is a real move-and-feel feeling, a real interaction between the surgeon and the robot," explains Dr Stephen Wu Wing-cheung, head of the hospital's department of orthopaedics and traumatology.

For surgeons, the experience of working with a robot can be heady. "It feels as if a very experienced buddy is working with me and I can reproduce the same accuracy in every single patient," says Dr Tang Wai-man, a specialist in orthopaedics and traumatology at the Sanatorium's orthopaedic and sports medicine centre. "Dr Wu and I first saw [Rio] advertised in a medical journal, and we were a bit sceptical, but the moment we saw this robot arm working, we fell in love with it."

Knee pain is a debilitating condition common among the aged. According to the experts, Asian patients tend to consider surgical treatments later than their Western counterparts and their knees tend to be smaller, thereby making intricate joint surgeries like partial knee replacements much more difficult to perform. These challenges are exacerbated by the lack of surgeons in Asia who are experienced in partial knee replacement surgeries.

The Rio system does away with all of these problems. Wu says that with the robot, surgeons can perform trickier surgeries with less hands-on experience. "In the past, if someone wanted to learn how to do a partial knee replacement, they would have to shadow someone very experienced, and it still wasn't perfect," he says.

"But if we can digitalise everything, then what used to be described in terms of feelings becomes something that can be quantified. It becomes easier to tell my trainees what we mean when we say 'make it tighter' or 'make it softer'. We can pass along the experience more easily."

Tang says the Rio system can also do hip surgery and potentially ligament and even spinal surgery.

Robotic procedures can be done more quickly with a smaller incision, and patients spend significantly less time under anaesthesia. While traditional knee replacement surgery used to take between 60 and 90 minutes, the robotic equivalents can be completed in as little as half an hour. The surgeries themselves are also more precisely done. "The robot is less invasive and preserves the natural anatomy of the knee better," Wu says.

But other types of robotic surgery don't always have the same benefits. A procedure using the da Vinci system, for example, can sometimes actually take longer than the same one performed by a surgeon, but its increased accuracy, reproducibility and ability make getting to those hard-to-reach areas less invasive.

Surgical robots have the potential to improve the patient experience dramatically. Lei Soi-peng was one of Wu's first patients. She used to work in a restaurant, walking up and down stairs for 10 hours a day, causing her severe knee pain. She tried Western and Chinese medicine and acupuncture, but nothing helped.

Finally, she agreed to have a partial knee replacement at a public hospital. This was before the days of robotic surgery, and her recovery was long and arduous. The pain never truly went away, and it wasn't long before her other knee began to fail. "It reached the stage that I would trip over all the time, and I was taking four to five painkillers a day just to keep walking."

Then the doctor told her about new robotic surgeries for the knee. She says she was bothered by the idea of being worked on by a robot, but the pain had become so bad, she couldn't think about anything else.

"It was like a rebirth," she says of the effects of the robot-assisted procedure. After her previous knee surgery, it took her nine days to get out of bed, but this time she was up and walking with the help of a physiotherapist in just 10 hours. She was walking on her own in only three days. While recovery from the previous surgery took months, this time Lei was swimming after only 20 days and fully recovered in 45. The robot left her with only 20 stitches, and although both procedures were painful, the robotic one healed much more rapidly.

But robotic surgeries can have a downside. The biggest drawback is cost. Hong Kong Sanatorium would not reveal the price of the knee replacement surgery, but says it costs 50 per cent more than the traditional alternative. However, Tang points out there will be cost savings with a shorter hospital stay and faster rehabilitation.

Robotic surgery is more expensive because the robots are made by only one or two companies, which have a tight hold on the market. With no competition, prices remain high. There is also the high cost of maintaining and operating the machinery. "The current robotic system costs about HK$20 million with a yearly maintenance cost of over HK$1 million. Each procedure needs [single-use] instruments, which cost HK$2,000 each," says Law.

What's more, robots can't revolutionise all surgery. There are many types in which the hands of an experienced surgeon are preferable to even the most advanced machine; these tend to be the more invasive, less predictable procedures such as abdominal surgeries.

Dr Marty Makary, an associate professor of surgery at Johns Hopkins University's School of Medicine in the US, says there are no randomised, controlled studies showing patient benefit in robotic surgery. "New doesn't always mean better," he says.

Makary led a study published last year in May that found about four in 10 hospital websites in the US publicise robotic surgery, with most touting its clinical superiority. He wrote in the , that the promotional materials on the hospital websites overestimate the benefits of surgical robots, largely ignore the risks and are influenced by the product's manufacturer. Makary and his team analysed 400 randomly selected websites from US hospitals of 200 beds or more.

Both Wu and Tang laugh at the idea that the era of the surgeon is coming to an end. "No, absolutely not," says Wu. "We still need to talk to our patients. The robot is merely a tool, a very accurate and important tool."

Tang agrees: "Human beings are still the most important. The computer, yes, it is very good, but it still needs to be controlled by someone with a human brain."

Hou adds: "I believe good surgical training is still the essential ingredient." He quotes Albert Einstein: "The human spirit must prevail over technology."