Reviewed by Dr Vishal Pai
A robotic knee replacement is a total knee replacement or a partial knee replacement in which Dr Vishal Pai plans your operation on a 3D model of your knee and uses a robotic arm to carry out that plan precisely. This page covers how it works, who it suits, recovery, what the research shows and the risks.
At a Glance
- A CT scan of your knee is used to build a 3D model, so Dr Vishal Pai can plan your knee replacement before surgery. He controls the operation throughout.
- The robotic arm helps place the implant closer to the plan, with fewer implants positioned outside the target range than with conventional surgery.
- During surgery, the robot measures how tight the ligaments are, so the knee can often be balanced with fewer ligament releases.
- Dr Vishal Pai uses the robot for two main reasons: to plan and deliver a personalised alignment for your knee, and to plan more complex knee replacements, such as after a fracture or with metalwork from earlier surgery.
- Trials and national registries show good results and revision rates in line with conventional surgery, and longer-term follow-up is continuing.
What is a robotic knee replacement?
A robotic knee replacement is a total or partial knee replacement done with the help of a robotic arm. The surgeon controls a saw attached to the arm. The arm keeps the saw within boundaries set by the surgeon’s plan. In Australia, about 4 in 10 total knee replacements and about half of partial knee replacements are now done with robotic assistance.[1]
The first modern knee replacement was performed in 1968, and implants and techniques have been refined ever since. Most people get good pain relief and better movement after a knee replacement, but about 1 in 10 people are not satisfied with the result.[2] Surgeons continue to look for ways to improve this, and robotic surgery is one of them. There are four main techniques:
- Conventional. Metal guides, called jigs, help the surgeon make the bone cuts that the implant sits on. The jigs are positioned using landmarks within the knee. These landmarks vary between patients, so there is some variation in the final position of the implant.
- Navigated. Trackers attached to the leg send information to a computer, which helps the surgeon position the jigs more accurately. Australian registry data show no overall difference in revision rates with navigation, although there may be a small benefit in people under 65.[1]
- Patient-specific. A scan of your knee is used to make a custom-made cutting guide, and the surgeon makes the bone cuts with a standard saw. The implant itself is not custom-made. Occasionally the guide does not fit the knee accurately during surgery, and the surgeon switches to a conventional technique.
- Robotic. Robotic knee replacement builds on computer navigation. A CT scan is used to plan the operation in 3D, and the robotic arm guides the saw to that plan. During surgery, the robot also measures how tight the ligaments are.
Why does Dr Vishal Pai use the robot?
Dr Vishal Pai uses the robot for two main reasons: to plan and deliver a personalised alignment for your knee, and to plan more complex knee replacements.
1. A personalised alignment for your knee
Everyone’s knees are different. Some people are born with straight knees. Some have knees that bow outwards, called varus or bow-legged alignment. Others have knees that angle inwards, called valgus or knock-kneed alignment.
The traditional approach to knee replacement was to make every knee straight, whatever its natural shape. More recently, surgeons have been exploring a personalised alignment. The implant is positioned to recreate the alignment you had before arthritis developed, with small adjustments so that the ligaments and soft tissues around the knee are balanced.
Dr Vishal Pai follows a personalised alignment approach. The robot gives him detailed information about your knee and lets him carry out the plan accurately, so he can achieve the alignment planned for you. This is his preference. Research into personalised alignment is continuing.
2. Planning a more complex knee replacement
Some knee replacements are more complex than usual. Examples include a knee where bone has been worn away or lost, a thigh bone or shin bone that healed in the wrong position after a fracture (a malunion), and plates, screws or rods left in the bone from earlier surgery. In these knees, the landmarks and metal guides used in conventional surgery can be unreliable, and old metalwork can get in the way of the standard instruments.[3]
In Dr Vishal Pai’s view, this is where the robot is most useful. The CT scan shows the shape of the bones, any deformity and any metalwork in 3D before surgery. He can plan the size and position of the implant around them, see where bone is missing, and check whether the implant would clash with existing metalwork. During the operation, the robotic arm guides the bone cuts to that plan, without relying on guides that assume normal anatomy.[3]
Who might need a robotic knee replacement?
A knee replacement relieves pain from advanced knee arthritis. When the cartilage in the knee wears away, bone rubs on bone and the knee becomes painful and stiff. Early on, non-surgical treatment such as physiotherapy, strength training, weight loss and anti-inflammatory medication can help. When arthritis is advanced and these measures no longer control your symptoms, a knee replacement can reduce pain and improve how well you move.
The bigger decision is whether you need a knee replacement at all, and whether a total or a partial knee replacement suits your knee. Read more about who might need a total knee replacement and about partial knee replacement. Dr Vishal Pai uses the robot for both total and partial knee replacements, and it can be particularly helpful if your knee replacement is more complex.
What is involved in a robotic knee replacement?
The steps involved in a robotic knee replacement include:
1. CT scan
A CT scan of your knee before surgery is used to build a 3D model.
2. Planning your implant
Dr Vishal Pai uses the model to plan the size and position of your implant.
3. Checking the plan against your knee
During the operation, small pins are placed in the thigh bone and shin bone so the robot knows where the knee is. Landmarks in your knee are checked against the model before any bone is cut.
4. Balancing the knee
The robot measures how the knee moves and how tight the soft tissues are, so Dr Vishal Pai can fine-tune the plan before the final cuts.
5. Making the bone cuts
Dr Vishal Pai makes the bone cuts with the robotic arm, which keeps the saw within the planned boundaries. The implant is then fixed in place.
Which robot and implants does Dr Vishal Pai use?
Dr Vishal Pai has trained in Australia and overseas to use the Mako robot. He uses it with the Stryker Triathlon total knee replacement and the Stryker Restoris partial knee replacement. Both implants have long track records on the Australian Orthopaedic Association National Joint Replacement Registry:
- About 95 in 100 cemented Triathlon total knee replacements had not needed revision at 15 years.[1]
- About 96 in 100 Restoris partial knee replacements had not needed revision at 5 years.[1]
How long does it take to recover from a robotic knee replacement?
Recovery after a robotic knee replacement follows the same plan as after a conventional one. After a total knee replacement, as a rough guide:
- Day of surgeryYou will usually take a short walk with crutches and put weight on your new knee.
- 3 to 4 daysYou will usually go home from hospital.
- 2 weeksYour wound is checked at your first follow-up appointment.
- 3 to 4 weeksYou can gradually stop using crutches.
- 6 weeksThis is the earliest you can return to driving.
- 8 weeksBy this stage, Dr Vishal Pai expects your knee to straighten fully and to bend beyond 90 degrees.
- About 12 monthsMost of your recovery is complete.
Recovery after a partial knee replacement is usually quicker. For more detail, see recovery after a total knee replacement and partial knee replacement.
What results can you expect?
Accuracy. Robotic surgery places the implant closer to the plan, and fewer implants end up outside the target range.[4][5]
Soft-tissue balance. Because the robot measures how tight the ligaments are before the bone cuts are made, the knee can often be balanced by fine-tuning the position of the implant rather than by releasing (cutting or stretching) ligaments. Studies report fewer ligament releases with robotic surgery.[6][7] Whether this improves long-term results is still being studied.[7]
Function and recovery. Two randomised trials have compared robotic and conventional knee replacement at 12 months. The larger one used the same robot and implant that Dr Vishal Pai uses. It found similar knee function, pain, hospital stay and complications in both groups. Most surgeons in that trial used a traditional straight alignment, and patients are being followed for 10 years.[4] A second trial, using a different robotic system, found better knee scores, less pain and higher satisfaction at 12 months in the robotic group.[6]
Personalised alignment. Some trials report better knee scores in the first few years with a personalised alignment, while others find no clear difference. Revision rates have been similar.[8][9]
How long the knee lasts. In Australia and the UK, revision rates after robotic total knee replacement have been similar to conventional surgery so far.[10][1] Robotic surgery is relatively new, so most robotic knees have been followed for less than 5 years, and longer-term results are being collected.[1]
Partial knee replacement. Pooled analyses of published studies report fewer revisions after robotic partial knee replacement.[11] In the Australian registry, one analysis found a lower revision rate with robotic assistance after a few years, although the number of people followed for that long is still small and the registry’s overall summary reports no difference.[1] The UK registry has found similar rates so far.[10]
What are the risks and complications?
Every operation carries risks, and Dr Vishal Pai goes through them with you before you decide. The risks are largely the same as for any knee replacement. A few relate to the robot itself:
- Infection, in less than 1 in 200 people.
- Blood clots in the leg.
- Stiffness, which occasionally needs a manipulation under anaesthetic if the knee is not bending or straightening by 6 to 8 weeks.
- Ongoing pain or dissatisfaction. About 1 in 10 people are not satisfied with the result.[2]
- Pin-site problems are uncommon. About 1 in 100 people have a problem where the tracking pins were placed, most often wound irritation or infection.[12] A break in the bone through a pin hole happens in about 1 in 1,000.[13]
- A slightly longer operation and a CT scan. The operation takes about 10 minutes longer on average.[4] The CT scan before surgery involves a dose of radiation.[14]
Rarely, the knee is unstable, the bone breaks during surgery, the implant loosens, or a nerve or blood vessel near the knee is injured, and further surgery may be needed. You will receive a written information sheet with the full list of risks.
Where does Dr Vishal Pai consult and operate?
Dr Vishal Pai consults at Sandringham Orthopaedic Specialists, Suite 1, 60 Bay Road, Sandringham. He performs robotic knee replacements at Calvary Holmesglen Private Hospital, 490 South Road, Moorabbin, in Melbourne’s south-east. Patients come from across Bayside, Glen Eira and the Mornington Peninsula, and some travel from regional Victoria.
The surgeon’s fee, Medicare rebate and health fund costs for a total knee replacement, including one done with robotic assistance, are set out in what a knee replacement costs.
References
Show all 15 referencesHide references
- Lewis P et al. 2025. Hip, Knee and Shoulder Arthroplasty: 2025 Annual Report. Australian Orthopaedic Association National Joint Replacement Registry.
- DeFrance M et al. 2022. Are 20% of patients actually dissatisfied following total knee arthroplasty? A systematic review of the literature. The Journal of Arthroplasty.
- Vu D et al. 2026. Robotic-assisted total knee arthroplasty in post-traumatic and previously operated knees with retained hardware: practical decision-making workflow. Journal of Robotic Surgery.
- Parsons H et al. 2026. Robotic-arm-assisted versus conventional total knee replacement (RACER-Knee): a pragmatic, multicentre, participant-masked and assessor-masked, superiority, randomised controlled trial. The Lancet. Funded by the UK National Institute for Health and Care Research; Stryker supplied equipment and training.
- Riantho A et al. 2023. Radiographic outcomes of robot-assisted versus conventional total knee arthroplasty. JBJS Open Access.
- Bollars P et al. 2025. Imageless handheld robotic-assisted total knee arthroplasty showed better clinical outcomes than conventional total knee arthroplasty: a randomized controlled trial with preliminary results at 1-year follow up. The Knee.
- Clapp I et al. 2025. Robotic-assisted primary total knee arthroplasty requires fewer soft-tissue releases and is associated with a larger reduction in early postoperative pain. The Journal of Arthroplasty.
- Mohamed A et al. 2026. Kinematic alignment versus mechanical alignment in total knee arthroplasty: a systematic review and meta-analysis of medium to long-term outcomes. Musculoskeletal Surgery.
- Gusho CA et al. 2025. No superiority of total knee arthroplasty alignment philosophies: a network meta-analysis comparing mechanical, anatomical, kinematic, restricted kinematic, and functional alignment among randomized controlled trials. JBJS Reviews.
- Mohammad HR et al. 2026. Early national comparison of robotic versus conventional knee replacements for arthritis using National Joint Registry data: target trial emulation study. BMJ.
- Xiang P et al. 2026. Comparative analysis of revision causes between robotic-assisted and conventional manual unicompartmental knee arthroplasty: a systematic review and meta-analysis. Knee Surgery & Related Research.
- Di Carlo G et al. 2026. The dark side of precision: pin-related complications in computer-navigated and robotic-assisted knee arthroplasty. Journal of Clinical Medicine.
- Peñaherrera-Carrillo C et al. 2026. Periprosthetic fractures associated with pin placement in robot- or navigation-assisted total knee arthroplasty: a systematic review and meta-analysis. Journal of Robotic Surgery.
- Ponzio D et al. 2014. Preoperative mapping in unicompartmental knee arthroplasty using computed tomography scans is associated with radiation exposure and carries high cost. The Journal of Arthroplasty.
- Batailler C et al. 2020. MAKO CT-based robotic arm-assisted system is a reliable procedure for total knee arthroplasty: a systematic review. Knee Surgery, Sports Traumatology, Arthroscopy.
Frequently asked questions
Does robotic surgery give a better result than conventional surgery?
How long will a robotic knee replacement last?
Does the robot do the operation?
No. Dr Vishal Pai performs the operation and controls the saw. The robotic arm keeps the saw within the boundaries of the plan he has made for your knee.
Will I need any extra tests?
Yes. You will need a CT scan of your knee before surgery to build the 3D model used for planning.
Can a partial knee replacement be done robotically?
Yes. Dr Vishal Pai uses the robot for both total and partial knee replacements.
Next step
Talk through your options
If you are weighing up a knee replacement, Dr Vishal Pai can examine your knee, review your scans and explain all your options, including treatment without surgery.