Replacing your joint with the help of a robotic arm

Replacing your joint with the help of a robotic arm

November 23, 2021

Doctor in Article:

Replacing your joint with the help of a robotic arm
Dr Lee Chong Meng

Replacing your joint with the help of a robotic arm

The original article can be found at The Star:


As our nation heads towards becoming an ageing one, we can expect to see an increase in people suffering from joint aches and pains.

The likely cause: wear and tear of the joints or osteoarthritis, where the cartilage within a joint begins to break down and the underlying bone begins to change.

While there is nothing much you can do to prevent it, there is no cause for alarm either.

“Everyone is going to get osteoarthritis at some point – it’s like your car tyres, they will wear out eventually to some degree,” says consultant orthopaedic surgeon Dr Lee Chong Meng.

“Most patients will end up having treatments such as medication, physical therapy or lifestyle modification.

“It’s only when those methods don’t work that we consider joint replacement surgery, but we will first assess the patient and discuss how much the arthritis is affecting their life.”

For a better life

Joint replacement means removing part or all of a damaged joint and putting in an artificial one – which can be made of plastic, metal, ceramic, or a combination of materials – to allow the limb to move without pain.

The joints that are usually replaced are the hip and knees.

More than a million such surgeries are carried out in the United States annually, making it one of the most common orthopaedic procedures performed today.

“Joint replacements are intended to relieve pain and improve quality of life, so that the grandma can run around to look after the grandkids or go on a holiday and walk without pain.

“With some old people, we are the last person they will consult as they will bear the pain for a long time, be in a wheelchair, etc, until nothing works – then they will seek help.

“With the younger group, they want to enjoy life and will consult us earlier,” says Dr Lee.

His youngest patient was 18 when she had both hips and knees replaced due to having juvenile rheumatoid arthritis since the age of four.

She was in a wheelchair, and being a teenager then, suffered a lot of psychosocial issues.

Dr Lee recalls: “I could have told her to go away and come back when she is 60, but I told the parents to consider joint replacement surgery. “However, they had to understand that she would need a revision surgery, maybe at 40 or 50 years old, as the artificial joints have a lifespan of 20 to 30 years. “They accepted it because their daughter’s condition was bad.”

Post-surgery, her quality of life improved – she started walking again, went to university, migrated and got married.

“Imagine, if we didn’t do this, her life would have been wasted.

“The downside is that she would need another operation.

“So there is really no fixed age for the surgery as it depends on the situation and stage of arthritis.

“But we prefer doing replacements in older people (65 and above), so that hopefully, this will be the only operation they will have in their lifetime,” he says.

If only part of the joint is damaged, then only partial joint replacement is necessary, as opposed to total joint replacement where the damage is severe.

People with bow legs are predisposed to osteoarthritis, but osteoarthritis also leads to bow legs, and total knee replacement surgeries will straighten the leg out.

“Patients tell me they are taller after both legs have been operated on,” Dr Lee says with a laugh.

Enter the robot

The majority of joint replacement surgeries in Malaysia are done by hand or via computer navigation, but technology is improving all the time.

While robotic technology is already being used in many medical disciplines, the use of the robotic arm in orthopaedics has only just recently been introduced here.

Basically, the robotic arm-assisted joint replacement surgery uses a CT (computed tomography) scan or X-ray data, along with robotic software, to generate a 3D virtual model of the joint to help the surgeon create a personalised pre-operative plan.

No, the robot does not function independently; instead, the surgeon guides the handheld robotic device within the predefined area.

This helps provide more accurate placement and alignment of the implant.

Says Dr Lee: “In the old days, we had to rely on our naked eyes to cut the bone and put the implant – if we cut it wrongly, the knee will be malaligned and it will wear out fast, just like car tyres. “And if the knee remains bent after surgery, then its function is affected. “So, there were many malaligned knees.”

Then came computer-navigated technology, which has superior results, but still has a plus-or-minus three degree margin of error. This is because it is the surgeon who inputs the information into the computer; if he misjudges, there is a chance of error. With the robotic arm, the error is less than one degree.

“This semi-active robot has an arm and is very clever. “Firstly, because the robot can see more than we can, it guides us to make a smaller incision. “Secondly, there is less soft tissue injury around the joint – a surgery itself is an injury and an insult to the body. “Being humans, we might cut more soft tissue than necessary, but the robot knows where to cut and when to stop, so if we go into the ‘hectic’ zone, it will automatically stop. “There is also less bleeding as it is highly accurate and precise,” says Dr Lee, who is among the first few doctors in the country to use this state-of-the-art technology for total/partial knee and total hip replacements.

Highly accurate


Two days prior to surgery, the surgeon and his team will discuss the case and procedure, after the robot has indicated the best placement of the implant for maximum function.

There are two types of joint replacement surgeries: cemented and uncemented.

In cemented surgeries, the surgeon will pour liquid cement on the natural bone to glue it to the implant and keep it in place.

It’s mostly suitable for older patients, whose bones may not grow, especially if they are osteoporotic.

“In younger patients who are more active, we use the uncemented type because the cement is not going to be able to withstand the demands placed on it.

“The uncemented surface is rough, and when we place the implant, the new bone grows into its spaces, holding it in place without the need for cement,” Dr Lee explains.


The finished “product” can be viewed even before surgery commences, so that doctors can adjust or tweak things.

“In the past, we would do the operation and second-guess ourselves by asking, ‘Did I cut the bone right?’.

“We only see the X-ray the next day, by which time it is too late for adjustments.

“Here, during the operation, the robot will execute the plan, and if we are a little bit off, the robot will stop – just like a teacher who will smack you if you’re wrong.

“There are so many checkpoints throughout the whole process that it’s hard to get things wrong.

“There are not many decisions to make during the operation,” he says.


Studies show that robotic surgeries result in better outcomes, compared to conventional joint replacement surgeries. These include shorter hospital stays, less post-operative pain, a more natural feeling of the limb, and a quicker return to normal activities.

Robotic surgery takes about 10 minutes longer than the one-hour conventional surgery.

Patients will spend one to four days in the hospital post-surgery, depending on the type of surgery and their recovery process. They should be able to resume most activities after six weeks. However, high-impact or contact sports are discouraged after surgery.


Says Dr Lee: “You can run across the road to save your life, but we don’t encourage running as an exercise because a high-impact activity will wear out the joint faster. “But some patients don’t listen and have climbed mountains and gone skiing three months after surgery.”


He explains: “The knee joint is an enclosed space, so when you apply a sudden brake, it can affect the bone and cause lesions, unlike your car brakes where the particles will fly out into the atmosphere when you brake.”

So, in order to preserve the replacement joint, it’s best to stick to activities such as doubles tennis, walking, swimming, golfing, light hiking and other low-impact sports.

Do some ‘shopping’


Before agreeing to a joint replacement surgery, Dr Lee encourages patients to shop around for doctors and opinions.

“If a surgeon tells you, you need an operation, go for a second or third opinion until you’re happy that it is the only option. “For a lot of patients who see me – I may be the fourth doctor they have consulted! “Then a patient might ask, why does one surgeon or hospital charge so much more than the other?

“It is important for patients to understand what type of implant is being put in as the cost will vary according to the material used.

“Every year, a new generation of implants with better resistance comes out, so the newer the model, the more expensive it is – and theoretically, it should last longer,” he says.

The robotic arm is not available in all hospitals as it costs a few million ringgit, hence only big hospitals can afford to buy it.

Dr Lee says: “Patients have to pay for the use of the robot and disposables, i.e. things that we feed into the robot that can only be used once. “A single total knee replacement costs around RM30,000 and using the robot will cost another RM2,000 to RM3,000 extra. “As a surgeon, I think it is worth it, but in the end, it is the patient who decides.”


About OSC:

Orthopaedic Specialist Centre (OSC) is the brainchild of four highly-experienced Malaysian orthopaedic specialists, who have come together to create an innovative centre of excellence purely focused on bone and joint care. Using their decades of experience in practice, they have embarked on a new mission for Malaysian orthopaedics. At OSC, the patient’s journey from treatment to recovery is accompanied by elevated levels of personalised expertise and empathy, in order to make a real difference to our patients’ lives. In contrast to large, faceless hospitals, OSC is a uniquely intimate medical boutique, one that puts meticulous, tailored care at the heart of the patient experience. OSC aims to redefine orthopaedic care in Malaysia, by making world-class treatment comfortable, cost-effective and attainable for the whole community. For more information, please visit