Robotic Knee Replacement (ROSA)

What is the ROSA® robotic technique

The ROSA® Knee system is a robotic assistant that uses real-time information to support the surgeon in the accurate positioning of the implants during total knee replacement. The surgical plan is adapted to the unique anatomy of each patient, so that the new joint is placed with the greatest possible accuracy.

It is important to stress that the ROSA® system does not operate autonomously. On the contrary, it serves as an advanced tool that enhances —and does not replace— the skill and judgement of the surgeon, who remains fully in charge at every step of the operation.

The evolution of knee replacement

Total knee replacement is one of the most successful operations in modern medicine, with excellent results over decades. Conventional techniques, however, rely to a large extent on the surgeon’s experience, on manual instruments and on visual assessment during the operation.

Robotic-assisted surgery came to enhance this process, offering accuracy that is difficult to achieve with manual instruments. It is not a replacement for the surgeon, but a sophisticated tool that translates a detailed, individualised plan into equally accurate execution. The ROSA® Knee system fits precisely into this philosophy, combining advanced imaging, individualised planning and real-time feedback.

Indications for robotic total knee replacement with ROSA®

The ROSA® robotic system is intended mainly for patients with early to mid-stage osteoarthritis of the knee. Osteoarthritis is a degenerative joint disease characterised by the progressive destruction and eventual loss of cartilage, resulting in painful bone-on-bone contact.

The symptoms of osteoarthritis —pain, swelling and reduced range of motion— significantly affect everyday activities. The ROSA® system is particularly beneficial for patients who no longer respond to conservative treatment (medication, physiotherapy and lifestyle changes) and are candidates for joint replacement.

Preparing for the operation

Preparation for surgery with the ROSA® system involves several steps, similar to those of a standard total knee replacement (full pre-operative, cardiological and anaesthetic assessment). One key difference, however, is the use of advanced imaging technology: before the operation a series of radiographs is taken, from which detailed three-dimensional images of the patient’s knee are created.

These images allow the surgeon to draw up an individualised surgical plan that takes into account the specific anatomical features of each knee. This individualised approach ensures that the operation is tailored for the best possible outcome.

How the operation is performed with ROSA®

The surgical procedure with the ROSA® system resembles that of a conventional total knee replacement, but is enhanced by robotic assistance. During the operation, the system works using optical trackers and a special miniature camera attached to the patient’s limb, in order to follow the exact position of the knee in real time.

This continuous tracking allows adjustments even for the slightest movements, ensuring that the surgical plan is executed with high accuracy. The system provides the surgeon with real-time data, enhancing their ability to position the implant with unique precision and to balance the ligaments correctly — two factors directly linked to the function and longevity of the prosthesis.

Why accuracy matters

A reasonable question is why accuracy of a few millimetres or degrees matters so much in knee replacement. The answer lies in the biomechanics of the joint: even small deviations in the alignment or orientation of the implants can change the way loads are distributed in the knee.

A prosthesis implanted with ideal alignment wears more evenly and more slowly, while correct balancing of the soft tissues ensures better stability and a more “natural” feel. This is precisely where the value of robotic assistance lies: it translates an individualised, accurate plan into equally accurate execution.

The benefits of robotic assistance in practice

The added value of ROSA® technology translates into specific, practical benefits for the patient:

• Accuracy of positioning: the implants are placed according to the individualised plan, with an accuracy that is difficult to achieve with manual instruments.
• Ligament balancing: the system helps the surgeon achieve the correct tension of the soft tissues throughout the range of motion, which is critical for the stability and “natural” feel of the joint.
• Potential preservation of more bone: accurate planning allows, where feasible, more “economical” bone removal.
• Consistency of outcome: robotic assistance reduces variability, making the result more predictable.

It is important to stress, however, that technology alone does not guarantee the result: the experience and judgement of the surgeon who operates it remain the decisive factor for success.

Common misconceptions about robotic surgery

There are some widespread misconceptions about robotic knee replacement that are worth clarifying. The most common is the impression that “the robot does the operation”. In reality, the ROSA® system has no autonomy whatsoever — every movement, every decision and every cut is made by the surgeon, who simply uses the system as a tool for accuracy and guidance.

A second misconception is that the robotic method is suitable only for “difficult” cases. In reality, the benefits of accuracy apply to all patients who are candidates for knee replacement, while they are particularly evident in cases of complex anatomy. Informing the patient about what robotic technology truly offers is part of proper preparation.

Post-operative care and recovery

Recovery from a robotic total knee replacement with the ROSA® system is generally faster than with traditional methods, thanks to the minimally invasive nature of the procedure. Post-operative care usually includes:

• Pain management: it is normal to have some stiffness and pain in the operated knee, which are controlled effectively with medication.
• Wound care: instructions are given for the care of the surgical incision and for activities such as driving and bathing.
• Resuming activities: most patients return to everyday activities within a few weeks.
• Regular follow-up: to assess the progress of recovery and address any questions.

Risks and complications

Although robotic total knee replacement with the ROSA® system is generally safe, like any surgical operation it carries certain possible risks:

• Pain: post-operative pain is common and is treated with medication.
• Bleeding: some blood loss is expected during and after the operation.
• Infection: although rare, it can occur and requires immediate treatment.
• Stiffness or instability: some patients may experience temporary stiffness or a feeling of instability.

Robotic assistance, through increased accuracy, helps to reduce some of these risks.

Robotic versus conventional knee replacement

The main difference is not that “the robot does the operation” — the surgeon remains fully in charge at every step. The difference lies in the level of planning and accuracy: with ROSA®, the plan is drawn up individually on a three-dimensional model and its execution is guided by real-time feedback. The result is more consistent positioning of the implants and, potentially, improved function and longevity of the prosthesis. In other words, it is an advance that enhances the surgeon’s skill.

Which patients are suitable candidates

Robotic knee replacement with the ROSA® system is as a rule intended for the same patients who are candidates for conventional total knee replacement: people with advanced knee osteoarthritis who no longer respond to conservative treatment and suffer from pain and severe functional limitation.

The particular value of robotic assistance becomes evident in cases with more complex or unusual anatomy, where the accuracy of individualised planning offers a substantial advantage. The final decision on each patient’s suitability is taken after detailed clinical examination, imaging and consideration of their medical history and needs.

Life after robotic knee replacement

A few months after the operation and completion of rehabilitation, most patients are free of chronic pain and have returned to activities they had given up: unrestricted walking, travelling, swimming, gentle exercise. The accuracy in positioning and alignment of the implants that robotic assistance provides contributes to a more natural feel of the joint and, potentially, to a longer lifespan of the prosthesis.

By maintaining a healthy body weight and favouring low-impact activities, the new joint can serve the patient for many years, without the limitations imposed by the previous wear.

Cost of robotic knee replacement

The cost of robotic total knee replacement depends on the type and materials of the implants, the use of robotic technology, the hospital and room category, the length of stay, and the patient’s insurance cover. In most cases, private insurance policies and insurance funds cover a significant part of the expense.

Precise information on cost is always provided on an individual basis, after the clinical examination and once the treatment plan has been defined. The practice is at your disposal for any relevant information.

More on the factors that determine the cost and on cover by insurance funds: Cost of surgery.

Frequently asked questions

What is the ROSA® Knee system?

It is a robotic system that assists total knee replacement, developed by Zimmer Biomet. It provides the surgeon with real-time data and individualised planning, for more accurate positioning of the implants.

Does the robot perform the operation by itself?

No. ROSA® is a precision tool that supports the surgeon, who plans and performs the operation and remains in charge at every step.

Which patients are suitable?

Mainly patients with early to mid-stage osteoarthritis of the knee who do not respond to conservative treatment and are candidates for joint replacement.

Is special imaging needed before the operation?

Yes. Before the operation a series of radiographs is taken, from which three-dimensional images of the knee are created for the individualised design of the surgical plan.

Is recovery faster with the robotic method?

Recovery is generally faster than with traditional methods, thanks to the minimally invasive nature and accuracy of the procedure. Most patients return to everyday activities within a few weeks.

What are the advantages over the conventional method?

Greater accuracy in positioning the implants, better alignment and ligament balancing, and potentially better function and longevity of the prosthesis.

Is the cost covered by insurance?

In most cases, private insurance policies and insurance funds cover part or all of the expense. The practice can give you detailed information.

Is the robotic method safer?

The increased accuracy in positioning the implants and balancing the ligaments helps to reduce certain risks and improve the consistency of the result. Like any operation, however, it carries the general surgical risks, which are minimised with correct technique and preparation.

How long does the operation take with the ROSA® system?

The duration is comparable to that of conventional total knee replacement. The time devoted to accurate planning and navigation is offset by the accuracy and consistency of execution.

Is a different rehabilitation needed?

The rehabilitation programme is similar to that of conventional knee replacement, but often faster thanks to the minimally invasive nature of the procedure.