Robotic and conventional knee replacement use the same implants and aim for the same result. Robotic assistance makes the operation measurably more accurate, but the largest trial to date (RACER-Knee, The Lancet 2026) found that in routine arthritic knees this precision did not change how patients felt at twelve months. That trial deliberately excluded the complex knees where planning precision plausibly matters most, and its ten-year follow-up is still running. Mr Hussain is certified on all three major robotic platforms, offers both approaches, and matches the technique to your knee.
What Is the Difference Between Robotic and Conventional Knee Replacement?
The implant is the same. The difference is how the bone is prepared and how the knee is balanced. Conventional surgery uses mechanical jigs and the surgeon's trained eye; robotic-assisted surgery adds a digital 3D plan and computer-controlled precision to execute it.
In both operations the worn joint surfaces are removed and replaced with metal and polyethylene components. Both are performed by the same surgeon, through a similar incision, with the same anaesthetic options and the same rehabilitation pathway. What the robot changes is the level of measured control over exactly where each cut is made and how the soft tissues are balanced around the new joint.
Does the Robot Actually Do the Operation?
No. The surgeon performs the operation from start to finish, and Mr Hussain is in complete control at every stage. The proper term is robotic-assisted surgery: the system holds the plan, tracks the knee in real time, and keeps the bone preparation within defined boundaries. It cannot move or cut anything on its own.
This is the most common misconception patients bring to clinic. A useful comparison is satellite navigation: the destination and the driving are the surgeon's, but the route is measured, displayed, and continuously checked rather than estimated.
How Conventional Knee Replacement Works
Conventional knee replacement relies on standardised cutting jigs, alignment rods, and the surgeon's physical assessment of the limb. It is a proven technique backed by decades of clinical success and millions of recorded operations.
The results speak for themselves. A landmark analysis in The Lancet found that 82% of knee replacements, overwhelmingly performed conventionally, are still functioning at 25 years.[7] Every knee replacement in England and Wales is independently tracked by the National Joint Registry, which is what makes that long-term evidence possible.[8] In experienced hands, conventional surgery remains an excellent operation, and it is the standard against which every new technology must prove itself.
What Robotic Assistance Adds
Robotic assistance adds three things: a customised 3D plan of your knee before any cut is made, real-time tracking of the limb during surgery, and computer-controlled bone preparation that keeps every cut to the plan. Depending on the platform, the plan comes from a CT scan (MAKO) or from image-free mapping of the joint surface during surgery (CORI), which avoids a scan altogether.
The plan is not just about the bones. The system measures how tight or loose the ligaments are through the full range of movement, so the balance of the new knee is assessed with objective data rather than feel alone. Defined boundaries around the cutting zone also help protect the surrounding ligaments and soft tissue during bone preparation.
Robotic vs Conventional at a Glance
| Aspect | Conventional | Robotic-assisted |
|---|---|---|
| Planning | Templating from X-rays, confirmed during surgery | Customised 3D plan (CT-based or image-free mapping) |
| Bone preparation | Mechanical jigs and cutting guides | Computer-controlled to the plan, with defined safety boundaries |
| Ligament balancing | Assessed by feel and experience | Measured objectively through the range of movement |
| Accuracy | Good in experienced hands; small outliers more common | Fewer alignment outliers in randomised trials |
| Early recovery | Standard enhanced-recovery pathway | Slightly less early pain in some trials; same pathway |
| Outcomes at 12 months | The same in the largest trial to date (RACER-Knee, The Lancet 2026) | |
| Track record | Decades of registry data; 82% of knees last 25 years | Excellent so far; long-term registry data still maturing |
| Operating time | Baseline | Roughly 10 minutes longer |
Is Robotic Knee Replacement More Accurate?
Yes. Greater accuracy is the most consistently proven benefit of robotic assistance. Randomised controlled trials show implants positioned closer to the surgical plan, with fewer alignment outliers than conventional jig-based instruments.[3] A 2025 meta-analysis pooling the available trials reached the same conclusion.[5]
Why does alignment matter? Implant position and soft-tissue balance are among the strongest surgical factors influencing how natural a replaced knee feels and how evenly it wears. Accuracy does not guarantee a better-feeling knee for every patient, but it removes one source of variation from a demanding operation. In 2025, NICE recommended robotic-assisted systems for joint replacement in the NHS, reflecting the strength of the accuracy evidence.[6]
Is Recovery Faster After Robotic Surgery?
Sometimes, in the early weeks. Several randomised trials have reported less pain in the first days, reduced soft-tissue trauma, and a quicker return to walking after robotic-assisted knee replacement.[4] These early gains are real in some studies but modest.
The honest, balanced picture is that the overall recovery journey is the same. You will follow the same enhanced-recovery pathway, the same physiotherapy milestones, and the same return to driving, work, and activity whichever technique is used. By three months, and again at twelve months, the largest trial found no measurable difference in the pain or function patients reported.[1]
What the Largest Trial Ever Conducted Has Just Shown
In August 2026, The Lancet published the RACER-Knee trial: 339 patients across ten UK hospitals, randomised to robotic-arm-assisted or conventional total knee replacement, with patients and assessors masked to which they received.[1] The Royal Orthopaedic Hospital Birmingham, where Mr Hussain practises, took part in the study.[2]
The result was clear. At twelve months there was no meaningful difference in the primary outcome, the Forgotten Joint Score, which measures how often patients are aware of their artificial knee in daily life. Pain, walking ability, and reoperation rates were comparable, and safety was equal, with no increase in serious adverse events. Robotic operations took around ten minutes longer.[2]
What RACER-Knee firmly establishes is this: patients choosing conventional surgery with an experienced knee surgeon are not settling for a second-class operation. What it can and cannot tell us beyond that depends on its design, and Mr Hussain sets out his reading below.
What RACER-Knee Does and Does Not Tell Us
RACER-Knee is a well-designed trial and its headline result deserves to be taken at face value: in routine, straightforward osteoarthritic knees, robotic assistance did not improve how patients felt at twelve months.[1] Mr Hussain agrees with that conclusion, and it is why he has never recommended robotic surgery on the promise of a better one-year outcome in a routine knee.
What the trial did not test is just as important. Its design excluded knees with osteoarthritis secondary to inflammatory disease or a previous fracture into the joint, and any knee needing stems, augments, custom implants, or revision surgery.[9] These are precisely the knees where a measured 3D plan is hardest to replicate with jigs, and where precision plausibly matters most. On those knees, the trial is silent.
Three further design points shape what can be claimed. The trial targeted conventional mechanical alignment, with surgeons free to adjust as they usually would, so the personalised alignment and balancing strategies that robotic platforms enable were not systematically tested: executing a conventional plan more precisely is not the same as testing a better plan.[9] It was powered to detect a twelve-point difference in the Forgotten Joint Score, so smaller average benefits, or benefits confined to subgroups, cannot be ruled out.[9] And it studied one CT-based platform with one cemented implant, so it says nothing about image-free systems such as CORI, cementless fixation, or partial knee replacement, where the accuracy argument is strongest.[9]
Honesty cuts both ways. The idea that selected complex knees benefit from robotic precision is a plausible, evidence-consistent hypothesis, not a proven fact, and the ten-year follow-up now underway is the right test of it.[1] That is why Mr Hussain offers both techniques and matches the tool to the knee in front of him.
Robotic assistance reliably delivers a more accurate operation. What it has not yet been proven to deliver is a knee that feels better one year on: the 2026 RACER-Knee trial found the same patient-reported outcomes at twelve months. Whether precision pays off in fewer revisions over decades is exactly what long-term follow-up is now tracking. The factor that matters most to your result remains the experience and judgment of your surgeon.
Are the Risks Different?
The core risks of knee replacement, infection, blood clots, stiffness, and the small chance of needing further surgery, are the same for both techniques, and RACER-Knee found no increase in serious adverse events with robotic assistance.[1]
The robotic approach does involve small additional incisions for the tracker pins that let the system follow the limb in real time. Pin-site complications are rare but recognised. Set-up also adds roughly ten minutes of operating time. Mr Hussain discusses these trade-offs openly at consultation, because an informed choice is only possible with the full picture.
Who Is Suited to Each Approach?
Most knees are suitable for either technique, so the decision rests on your individual anatomy, the pattern of joint wear, any previous surgery or retained metalwork, and your lifestyle goals. There is no single right answer that applies to every patient.
Robotic assistance earns its keep most clearly in knees that are harder to balance by eye: significant deformity, partial (unicompartmental) replacement where precise positioning is critical, and revision surgery. Conventional surgery remains a fully sound choice for routine knees, and it is the pragmatic option where robotic access is limited. The X-rays below show a knee from Mr Hussain's own archive, replaced with robotic assistance.
What Are the Cost Implications?
Robotic assistance costs the healthcare system more. The robotic platform, its instruments, and the extra operating time all add expense, and the NHS analysis run alongside RACER-Knee concluded the technology is not yet cost-effective for the NHS on first-year outcomes alone.[2] Some UK private hospitals pass a robotic premium on to patients.
In private practice this is reflected in the package price: robotic-assisted knee replacement carries a surcharge over conventional surgery. The reason is straightforward. Each robotic case uses single-use robotic instruments and consumables, the platform itself must be maintained and supported, and the operation takes slightly longer in theatre. Self-pay knee replacement remains a fixed, all-inclusive package covering the surgeon, implant, anaesthetist, and hospital stay, and the exact figure for your operation, robotic-assisted or conventional, is confirmed in writing after your consultation, with no hidden extras. All major UK insurers cover robotic-assisted knee replacement when it is clinically appropriate, and Wendy Richards, Mr Hussain's secretary, handles pre-authorisation with your insurer. Current package guidance is on the fees and insurance page.
Which Robotic System Does Mr Hussain Use?
Mr Hussain is one of a small number of UK surgeons certified on all three major robotic knee platforms: MAKO, ROSA, and CORI. His platform of choice is the image-free CORI system, which maps the knee directly during surgery, so no CT scan is needed, and supports partial, total, and revision knee replacement on one platform. In June 2026 he performed the Midlands' first CORI robotic revision knee replacement, one of the first in the UK.
How the operation itself works is covered on the robotic knee replacement in Birmingham page, and the reasons behind his choice of platform are explained in why Mr Hussain chooses the CORI system.
What Should You Do Next?
The best surgical approach for you depends on your anatomy, the state of your joint, and what you want your knee to do afterwards. That is a decision to make with a surgeon who offers both techniques and has no need to sell you either. A consultation involves an examination, standing X-rays of the knee under load, and an honest recommendation, whether that is knee replacement surgery in Birmingham or continued non-surgical care.
If you are weighing up your options, arrange a private knee consultation in Birmingham and get an answer that is specific to your knee rather than general to the technology.
Frequently Asked Questions
Does the robot actually do the knee replacement?
No. Mr Hussain performs the operation and is in complete control throughout. The robotic system contributes a 3D plan of your knee and keeps the bone preparation precisely to that plan. It cannot move or cut anything on its own.
Is robotic knee replacement more accurate than conventional?
Yes. Randomised trials consistently show that robotic assistance positions the implant closer to the surgical plan, with fewer alignment outliers than conventional jig-based instruments. Greater accuracy is the most clearly proven benefit of the technology.
Is recovery faster after robotic knee replacement?
Sometimes slightly, in the first weeks. Some trials report less early pain and a quicker return to walking. The largest trial to date, published in The Lancet in 2026, found pain and function were comparable at three and twelve months. The overall rehabilitation timeline is the same.
Are there extra risks with robotic knee replacement?
No meaningful extra risk has been shown. The 2026 Lancet trial found no increase in serious adverse events with robotic assistance. The robotic approach adds small tracker pin sites and roughly ten minutes of operating time.
Am I better suited to robotic or conventional knee replacement?
Most knees are suitable for either. The right approach depends on your anatomy, the pattern of joint wear, any previous surgery or metalwork, and your lifestyle goals. Mr Hussain assesses this at consultation and offers both techniques.
Does the RACER-Knee trial mean robotic knee replacement is not worth having?
No, but it sharpens the question. The trial showed that routine arthritic knees gain no measurable twelve-month benefit from robotic assistance. It deliberately excluded complex knees, tested only conventional mechanical alignment, and its ten-year follow-up is still running. For selected complex knees the benefit of precision remains a plausible but unproven hypothesis, which is why Mr Hussain offers both techniques.
Does robotic knee replacement cost more with Mr Hussain?
Yes. Robotic-assisted knee replacement carries a surcharge over conventional surgery, because each case uses single-use robotic instruments and consumables, the platform must be maintained, and theatre time is slightly longer. Your all-inclusive package price is confirmed in writing after your consultation, and all major UK insurers cover robotic-assisted knee replacement when it is clinically appropriate.
References
- Robotic-arm-assisted versus conventional total knee replacement (RACER-Knee): a pragmatic, multicentre, participant-masked and assessor-masked, superiority, randomised controlled trial. Lancet. 2026. Full text
- University of Warwick. Robotic assisted knee replacement gives the same patient outcomes as a surgeon only procedure. Press release, August 2026.
- Bollars P, et al. Improved accuracy of implant placement with an imageless handheld robotic system compared to conventional instrumentation in patients undergoing total knee arthroplasty: a prospective randomized controlled trial. Knee Surg Sports Traumatol Arthrosc. 2023;31:5446-5452. Full text
- Bollars P, Nathwani D, Albelooshi A, et al. 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. 2025;56:232-240. PubMed
- Robotic-assisted versus conventional total knee arthroplasty: a systematic review and meta-analysis of alignment accuracy and clinical outcomes. Ann Med Surg (Lond). 2025;87(2). PubMed
- National Institute for Health and Care Excellence. Cutting-edge robotic surgery gets green light as 11 systems are recommended. NICE, 2025.
- Evans JT, et al. How long does a knee replacement last? A systematic review and meta-analysis of case series and national registry reports with more than 15 years of follow-up. Lancet. 2019;393(10172):655-663. PubMed
- National Joint Registry for England, Wales, Northern Ireland and the Isle of Man. njrcentre.org.uk
- Griffin J, et al. Robotic Arthroplasty Clinical and cost Effectiveness Randomised controlled trial (RACER-knee): a study protocol. BMJ Open. 2023;13:e068255. Full text
This page is for general information and is not a substitute for a consultation. Whether robotic-assisted or conventional knee replacement is right for you is assessed individually.
Mr Shakir Hussain
Consultant Hip and Knee Surgeon at the Royal Orthopaedic Hospital Birmingham, with over 5,000 procedures and certification on all three major robotic knee platforms: MAKO, ROSA, and CORI.