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- Depending on the robotic system, planning may involve pre-operative imaging or mapping performed during arthroplasty.
- Your surgeon remains in control and can review and adjust the plan based on your anatomy and ligament balance.
- Robotic technology helps guide bone preparation and implant positioning rather than performing the operation independently.
If you are considering robotic knee replacement surgery, you may picture most of the technology coming into play once the operation begins. In reality, an important part of robotic-assisted surgery happens before any bone is cut.
The system helps your surgeon build a detailed picture of your knee, plan where the implants should sit and then check that plan against your actual anatomy during surgery. Importantly, the technology assists rather than replaces the surgeon.
What Robotic Assistance Actually Does in Knee Arthroplasty
Robotic knee replacement follows the same basic principle as conventional knee replacement: damaged joint surfaces are removed and replaced with artificial components.
What changes is the information available to your surgeon when planning and carrying out those steps.
A Surgical Tool, Not an Automated Surgeon
Despite the name, the robot does not independently decide how your knee should be replaced or perform the operation on its own.
Your orthopaedic surgeon remains responsible for the surgical plan, implant positioning and decisions made during the procedure. The robotic system provides computer-assisted planning, measurements and guidance to help the surgeon execute that plan.
This distinction matters because robotic knee replacement still relies on your surgeon’s assessment of your anatomy, joint damage and soft tissues.
Where the Technology Sits in the Operation
Robotic assistance can be involved at several stages.
Depending on the system, it may be used to create a virtual model of your knee, plan implant size and position, register your anatomy during surgery and guide bone preparation. Some systems also provide information about joint movement and ligament balance while the surgeon adjusts the plan.
What Stays the Same as Conventional Surgery
The fundamental operation does not change.
Your surgeon still needs to remove the damaged joint surfaces, prepare the bone, position the implants and assess the stability and movement of the reconstructed knee.
You will also still require anaesthesia and postoperative rehabilitation.
Building a 3D Picture of Your Knee
One of the central features of robotic knee replacement is creating a virtual representation of your knee that can be used for surgical planning.
How that model is produced depends on the robotic platform.
Imaging-Based and Image-Free Systems
Robotic knee replacement systems broadly include image-based and image-free, or imageless, platforms.
Image-based systems use pre-operative imaging, such as a computed tomography (CT) scan, to create a virtual 3D model representation of the bones around your knee. Your surgeon can then use this model to plan aspects such as bone resections, implant size and implant orientation before arthroplasty.
Image-free systems work differently. Instead of relying on a pre-operative scan to construct the model, anatomical landmarks and information about the knee are collected during the operation and registered with the robotic system.
Whether a Pre-Operative Scan Is Needed
You do not necessarily need a CT or magnetic resonance imaging (MRI) simply because you are doing a robotic knee replacement.
The requirement depends on which robotic platform your surgeon uses. CT- or MRI-based systems require the relevant imaging to build their model, while imageless systems can create the information needed for planning through intraoperative registration.
You will generally still have standard investigations and imaging to assess your knee and plan the replacement itself.
What the 3D Model Shows the Surgeon
The virtual model gives your surgeon a detailed representation of the bony anatomy relevant to the replacement.
Rather than planning around a generic knee, the surgeon can now work with measurements based on your own anatomy. Depending on the platform, the software can also be used to plan:
- The amount of bone to be removed
- The position of the femoral and tibial components
- Implant size
- Implant orientation
- Overall limb alignment
- The relationship between planned bone cuts and the reconstructed joint
Planning Implant Size and Position
Implants need to fit the prepared bone appropriately and work together as the knee bends and straightens.
With image-based robotic systems, your surgeon can virtually position different implant sizes and orientations before an arthroplasty. The software can show how changing one aspect of the plan affects other measurements.
However, a pre-operative plan is not necessarily the final plan. Your surgeon still checks it against what is found during the operation.
Mapping the Knee During Arthroplasty
Once you are in the operating theatre, the robotic system needs to understand where your actual knee sits in relation to the virtual information on screen.
Registration and Bone Landmarks
Registration involves identifying specific anatomical landmarks on the femur and tibia and recording them within the robotic system.
Tracking equipment allows the system to relate the physical position of your knee to the computer model. In image-based systems, this helps match your knee to the model created from your pre-operative imaging.
In imageless systems, more extensive intraoperative mapping is used to construct the virtual representation itself.
Checking the Plan Against Your Actual Anatomy
A scan provides valuable information about your bones, but surgery gives your surgeon additional information about the knee itself.
The planned implant positions and bone resections will be checked against your anatomy in the operating theatre before proceeding.
This is one reason robotic planning should not be thought of as simply creating a plan on a computer and following it unchanged. The system provides information, while your surgeon interprets it and decides whether adjustments are needed.
Assessing Ligament Tension Through Range of Movement
A knee replacement has to do more than line up correctly on an image. It also needs to remain appropriately balanced as you bend and straighten your leg.
Robotic and sensor-assisted technologies can provide objective intraoperative information about joint gaps and ligament balance.
Your surgeon can move the knee through different positions and assess how the soft tissues behave. This adds another layer of patient-specific information before finalising the implant position.
Considering robotic knee replacement? At Alps Orthopaedic Centre, your knee can be assessed to determine whether joint replacement is appropriate and how robotic assistance may fit into your surgical plan. Book a consultation here.
Adjusting the Plan Before Any Bone Is Cut
Having detailed measurements available during surgery allows your surgeon to review and refine the initial plan before any bone is cut. They can assess how different adjustments may affect alignment, implant position and the spaces within the knee before deciding how to proceed.
Fine-Tuning Implant Position and Alignment
Small changes to implant position can affect the overall reconstruction of the knee.
Robotic planning allows the surgeon to virtually adjust aspects of the femoral or tibial component before carrying out the planned bone cuts. The system can provide real-time information about how those changes affect alignment and planned resection depths.
The surgeon then decides which configuration is appropriate for the individual knee.
Balancing the Knee in Bending and Straightening
The knee also needs to function through a range of movement rather than in one fixed position.
During planning, your surgeon can assess the spaces between the bones when the knee is straight and when it is bent. Information about ligament tension can then be considered alongside the planned implant position.
If the knee appears too tight or loose in a particular position, aspects of the plan may be adjusted before the bone cuts are finalised. Robotic platforms can provide real-time information on these flexion and extension gaps to support this process.
Two Knees Are Rarely Planned the Same Way
Everyone differs in their natural limb alignment, bone shape, degree of arthritis, ligament behaviour and pattern of joint wear. Even your left and right knees are not necessarily identical.
Robotic planning gives the surgeon a way to account for these individual characteristics rather than relying solely on standardised measurements. The final plan still has to stay within appropriate surgical parameters, but it can be adapted to what the surgeon finds in your particular knee.
What the Planning Stage Means for You as a Patient
Much of the technical planning happens behind the scenes, but there are still things you may need to do before an arthroplasty.
Consultation with your orthopaedic surgeon is an opportunity to understand exactly how the robotic system being used works.
Pre-Surgery Day
Your pre-operative preparation will depend on your health and the robotic platform being used.
You may be asked to undergo:
- X-rays and, where required, CT or other imaging
- Blood tests and other pre-operative investigations
- A review of your medications and medical conditions
- Anaesthetic assessment where appropriate
- Prehabilitation or exercises to prepare for recovery
If your robotic system requires a specific pre-operative scan, your surgical team will arrange or advise you about this beforehand.
What to Expect on the Day
On surgery day, the procedure begins much like other knee replacements, including preparation and anaesthesia.
Once the knee is exposed, the robotic system is registered to your anatomy. Your surgeon can then verify the existing plan, assess the knee and make any appropriate adjustments before proceeding with bone preparation.
The robotic system assists during the planned stages, while the surgeon remains responsible for performing and directing the operation.
Questions To Ask at Your Consultation
If you are have been recommended robotic surgery, useful questions to ask include:
- Which robotic system will be used for my knee?
- Will I need a CT scan or other additional imaging?
- Can you change the plan during surgery?
- How does the system assess alignment and ligament balance?
- Why are you recommending robotic assistance for my knee?
- Am I having a partial or total knee replacement?
- What should I expect from rehabilitation afterwards?
These questions can help you understand not only what technology is being used, but why your surgeon considers it appropriate for you.
Speak to a Knee Specialist About Robotic Knee Replacement in Singapore
Robotic planning gives your surgeon detailed information about your knee anatomy, alignment and implant positioning before the planned bone cuts are made.
At Alps Orthopaedic Centre, Dr Jerry Chen has experience with robotic knee replacement platforms including MAKO, ROSA, VELYS and CORI. We also incorporate Enhanced Recovery After Surgery (ERAS) into our knee replacement programme to support mobilisation and recovery.
A consultation can help you determine whether robotic knee replacement is appropriate for your knee. Book an appointment today.
