When pain already limits walking, climbing stairs or standing for more than a few minutes, a knee replacement can restore freedom of movement — and robotic technology is one of the tools available to plan and carry it out.
The surgeon decidesThe robot does not operate on its own
What changes
Restoring Freedom of Movement
When knee pain already limits walking, climbing stairs or standing for more than a few minutes, and conservative treatments no longer help, a knee replacement can restore that freedom of movement. In selected cases, the Velys robotic system can be used to support the planning and execution of the surgery, in both total and partial knee replacement.
Robotic-assisted surgery is a precision tool at the service of the surgeon's decision — not a different kind of surgery, nor a guarantee of outcome.
The technology
What Velys Is
Velys is a surgical planning and assistance system that creates an individualised 3D plan based on your own knee imaging, and helps carry out the bone cuts with greater precision. The clinical decision always rests with the surgeon — the robot does not operate on its own, it is a precision tool.
It is the same type of system used, for example, at the Charité in Berlin, one of the largest university hospitals in Europe, with the same system and the same type of implant (ATTUNE).
Total or partial
Total Knee Replacement (TKA) vs. Partial Knee Replacement (UKA)
The type of replacement depends on the extent of the wear — not on the technology used to fit it.
Generalised wear
Total Knee Replacement (TKA)
Indicated when the wear affects the knee in a generalised way, in more than one compartment. It replaces the entire joint surface.
Localised wear
Partial / Unicompartmental Knee Replacement (UKA)
Indicated when the wear is confined to a single compartment of the knee. It preserves the rest of the joint, usually with a quicker recovery.
What the evidence shows
Why Consider This Technology
Robotics improves the precision of positioning — but it is a tool, not the only way to achieve good results. The evidence helps to frame expectations.
A study from the HSS (Hospital for Special Surgery, New York) involving 1.3 million patients (2010–2018) found a 90-day complication rate of 1.57% with robotic assistance, vs. 2.55% in conventional surgery (Arthroplasty Today).
According to the Mayo Clinic, the robotic arm controls the bone cuts with a precision of 0.5 mm.
The Charité (Berlin) uses the same Velys system with the ATTUNE implant, with millimetric positioning adapted to each patient's ligaments.
Not all major centres follow this route: the ENDO-Klinik in Hamburg, the largest specialist clinic in Europe (more than 1,700 replacements/year), instead relies on volume and accumulated experience with conventional technique. Robotics is a precision tool, not the only way to achieve good results.
Insurance and costs
Insurance Cover and Costs
Reimbursement for the use of the robotic system varies between insurers and health plans — not all cover this additional cost beyond the implant itself.
Before surgery, it is worth confirming directly with your insurer whether robotic-assisted surgery is included in your cover, or whether it entails an extra cost payable by the patient.
Step by step
What the Process Involves
1
Imaging-based planning
Pre-operative assessment using imaging of your own knee.
2
Individualised plan
Creation of a 3D plan adapted to your anatomy and ligaments.
3
Surgery
Velys-assisted execution, when indicated, under the surgeon's decision.
4
Recovery
The usual recovery from a knee replacement, with targeted physiotherapy.
Frequently Asked Questions
Questions About Robotic-Assisted Knee Surgery
The surgeon is the one who operates. Velys is a planning and precision tool: it creates a 3D plan from the imaging of your knee and helps carry out the bone cuts accurately. The clinical decision — the type of implant, the positioning, the balancing of the ligaments — always rests with the surgeon. The robot does not operate on its own.
In selected cases of total or partial knee replacement, when the additional planning and precision bring an advantage for the specific case. It is neither compulsory nor suitable for every patient — the indication is individualised and discussed in consultation, taking into account your anatomy, the degree of wear and your goals.
It depends on the extent of the wear. If the wear affects the knee in a generalised way, the indication is a total knee replacement (TKA), which replaces the entire joint surface. If the wear is limited to a single compartment, a partial knee replacement (UKA) may be indicated, which preserves the rest of the joint and usually has a quicker recovery.
It depends on the insurer and the plan; we recommend confirming beforehand, because not all cover this additional cost. The use of the robotic system may represent a cost beyond the implant itself — it is worth clarifying with your insurer before surgery whether it is included or whether it entails an amount payable by the patient.
The patient experience is similar to that of a conventional knee replacement: the anaesthesia, the post-operative period and the rehabilitation follow the same course. The surgical time may be slightly different depending on the case and the adoption phase of the technique, with no relevant impact on recovery. The aim of the technology is the precision of the planning and execution, not to change the way recovery happens.
The cost depends on the treatment pathway. SIGIC (Portuguese NHS): with a surgery voucher, the procedure is fully covered — no cost to the patient. Health insurance / subsystems: contracted surgery, according to your plan. Private: a personalised quote — as a guide, from €3,000 for arthroscopy (meniscus, ligaments or cartilage, including anterior cruciate ligament reconstruction) and from €8,000 for knee replacement. Final prices depend on the clinical case, hospital and implants. For an exact quote, book an appointment or see prices & quotes.
I collaborate as a clinical consultant with Johnson & Johnson MedTech.
References
Chen J, Chua HYJ, Lim JTE, et al. VELYS robotic-assisted total knee replacement leads to improved mobility, reduction in hospitalisation, surgical duration, and better psychological outcomes: a propensity score matched analysis. Arthroplasty. 2025;7(1):55. doi:10.1186/s42836-025-00342-x
Alton TB, Severson EP, Ford MC, et al. VELYS robotic-assisted total knee arthroplasty: enhanced accuracy and comparable early outcomes versus manual instrumentation during adoption. J Exp Orthop. 2025;12(1):e70163. doi:10.1002/jeo2.70163
Huang P, Cross M, Gupta A, et al. Early clinical and economic outcomes for the VELYS robotic-assisted solution compared with manual instrumentation for total knee arthroplasty. J Knee Surg. 2024;37(12):864–872. doi:10.1055/a-2343-2444
Doan GW, Courtis RP, Wyss JG, et al. Image-free robotic-assisted total knee arthroplasty improves implant alignment accuracy: a cadaveric study. J Arthroplasty. 2022;37(4):795–801. doi:10.1016/j.arth.2021.12.035
Morrison SR, Hall AJ, Clement ND, et al. Use of the VELYS robotic-assisted solution in knee arthroplasty: a scoping review. J Exp Orthop. 2026;13(2):e70726. doi:10.1002/jeo2.70726
Sappey-Marinier E, Aït Si Selmi T, Bonnin M, Schmidt A. Arthroplastie unicompartimentale du genou assistée par le robot VELYS. Maîtrise Orthopédique. 2025;(348). Hôpital de la Croix-Rousse / Centre Orthopédique Santy, Lyon.
References 1–5 indexed in PubMed.
NC
Dr. Nuno Camelo Barbosa
Orthopaedic Surgeon · Knee Subspecialist Hospital Lusíadas Porto · Hospital Misericórdia Vila do Conde · Paços de Ferreira
Total and Unicompartmental ArthroplastyRobotic-Assisted Surgery
Considering a knee replacement?
A specialist assessment determines whether you are a candidate for a replacement, whether it should be total or partial, and whether robotic assistance brings an advantage in your specific case.
