Robotic Complex Knee Replacement in London: Revision and Difficult Knees
Robotic complex knee replacement is surgery for knees that a standard replacement cannot manage well. Typical examples are a failing earlier replacement, severe deformity, lost bone, or old fractures and metalwork. Mr Sivan Sivaloganathan, Consultant Orthopaedic Surgeon in London, maps each of these knees on a 3D model before surgery. A robotic arm then guides the bone work he has planned.
Demand is real. The National Joint Registry recorded 5,732 first-time knee revisions in 2025, and 119,239 knee revision operations since its records began in 2003. Mr Sivaloganathan prepared for this work through fellowships in Montreal, Canada, and at Imperial College Healthcare NHS Trust, London.
Most people with knee arthritis need a first-time replacement without these extra problems. If that is you, his robotic-assisted partial and total knee replacement page is the place to start.
What Is Robotic Complex Knee Replacement?
A knee replacement counts as complex when the usual implants and steps are not enough. Versus Arthritis gives 3 common reasons: major bone loss from arthritis or fracture, major deformity, and weak main knee ligaments. A second or third replacement in the same knee, called a revision, falls in the same group.
These knees often need different parts. Versus Arthritis describes implants with longer stems fixed deeper into the bone. Some have linked parts that act like a hinge, and extra metal or plastic blocks can fill missing bone. His live page adds bone grafting, ligament reconstruction and custom implants for some cases.
The robotic step works the same way as in a first-time knee. Your knee is rebuilt on a screen in theatre, and the implant is sized and positioned before any bone is cut. Live readings then show whether the knee is balanced and stable, which matters most where the anatomy has already been changed.
Be aware that most published robotic data comes from first-time operations. The NJR’s 2026 robotic figures describe primary joint replacements, and NICE guidance HTG743 (2025) says more evidence on robotic orthopaedic surgery is still being collected.
Signs a Knee Replacement Is Failing, and When to Get Urgent Help
A replaced knee that hurts, swells or wobbles months or years later needs a proper review, not just painkillers. The NHS page on knee replacement complications lists ongoing pain, stiffness and an unstable knee as possible long-term problems.
| Your symptom | Possible cause | What to do |
|---|---|---|
| Pain in a replaced knee that returns or grows over months or years | Loosening, wear or arthritis spreading in a partial knee (NJR) | Book a review with Mr Sivaloganathan |
| Knee feels loose or gives way, often on stairs | Instability of the implant or ligaments (NJR, NHS) | Book a review |
| Knee still will not bend well about 6 weeks after surgery | Stiffness (Versus Arthritis) | Contact your surgical team about manipulation |
| Replaced knee turns hot, red and swollen, or the wound oozes, with a high temperature | Possible infection (NHS) | Urgent GP appointment or NHS 111 the same day |
| Sudden pain after a fall and you cannot take weight | Possible break in the bone around the implant (Versus Arthritis) | Go to A&E |
| Calf pain or swelling, with breathlessness or chest pain | Possible clot reaching the lungs (NHS) | Call 999 or go to A&E |
| Confusion, slurred speech, mottled skin or very fast breathing | Possible sepsis (NHS) | Call 999 or go to A&E |
Infection in a replaced joint is serious. The NHS septic arthritis page explains that an infected artificial joint may need to be removed and replaced once the infection has been treated.
Conditions Mr Sivaloganathan Treats with Complex Knee Replacement
- Loosening or wear of an earlier replacement: the NJR lists aseptic loosening, meaning loosening without infection, as the commonest reason for knee revision.
- Infection around a knee replacement: the second commonest reason (NJR), and the most likely cause of revision in the first year after surgery.
- Instability after a previous replacement: a knee that slips or gives way, 1 of the 5 commonest reasons for revision (NJR).
- Stiffness after a previous replacement: manipulation under anaesthetic is the commonest repeat knee operation, with 578 recorded in 2025 (NJR).
- Severe deformity: bow legs, knock knees or a bent knee beyond what a standard implant can balance (his site, Versus Arthritis).
- Bone loss or weak bone: from arthritis, fracture or earlier surgery, filled with metal blocks or graft (his site, Versus Arthritis).
- Old fractures or metalwork near the knee: plates or screws from a past injury that must be planned around (his site). Recent injuries are covered on knee injuries and meniscal repair.
- Inflammatory arthritis with an unstable knee: such as rheumatoid arthritis, which can loosen the ligaments (his site, NHS).
- A break around an existing implant: 377 operations for these periprosthetic fractures were recorded in 2025 (NJR).
Treatment Options for a Complex or Revision Knee
The right operation depends on why the knee is failing. The NJR groups revisions into single-stage operations and 2-stage operations, and records washouts and manipulations separately. Mr Sivaloganathan explains which applies to your knee, and why.
Complex First-Time Knee Replacement
This is a first replacement in a knee with severe deformity, lost bone, old metalwork or weak ligaments. Extra parts such as stems, blocks or a hinged design may be used (Versus Arthritis). His page gives 1 to 2 hours in theatre and 1 to 3 days in hospital. Deep infection occurs in roughly 1 in 100 knee replacements overall (Versus Arthritis).
Single-Stage Revision
The failed parts are taken out and new ones fitted in 1 operation. It is the usual route: 87.8% of first knee revisions in the NJR were single-stage. For infection, single-stage revision has been used twice as often as the 2-stage route in the past 5 years (NJR). The NJR puts re-revision at about 15% within 10 years.
Two-Stage Revision for Infection
The infected implant is removed, the infection is treated, and a new knee is fitted in a second operation. The NJR records 12.2% of first revisions as part of this route. The NHS notes that a replacement may follow once the infection has gone. Versus Arthritis says that, very rarely, uncontrolled infection ends in fusing the knee.
Washout with the Implant Kept
For some early infections, the joint is washed out and the implant is left in place. The NJR recorded 173 of these operations in 2025. It means 1 operation instead of 2, but it does not suit every infection.
Manipulation Under Anaesthetic for Stiffness
If a knee will not bend about 6 weeks after a replacement, Versus Arthritis says the surgeon may move it under anaesthetic, followed by intensive physiotherapy. No implant is changed. The NJR counted 578 of these procedures in 2025.
| Option | Usually chosen for | Source |
|---|---|---|
| Complex first-time replacement | Deformity, bone loss, metalwork or weak ligaments | Versus Arthritis, his site |
| Single-stage revision | Loosening, wear, instability and many infections | NJR |
| Two-stage revision | Infections not suited to a single operation | NJR, NHS |
| Washout, implant kept | Some early infections | NJR |
| Manipulation under anaesthetic | Stiffness about 6 weeks after surgery | Versus Arthritis, NJR |
Why Patients Choose Mr Sivaloganathan for Complex Knee Surgery
- Complex knee training: a fellowship in complex hip and knee reconstruction at HMR hospital, University of Montreal, backed by an international fellowship scholarship in 2021.
- Robotic and trauma training: a fellowship at Imperial College Healthcare NHS Trust joining robotic complex knee work with complex trauma, useful where old fractures change the knee.
- Hospitals: complex robotic surgery at King Edward VII’s Hospital in Marylebone and Chelsea Private Care on Fulham Road, with 4 further clinics for consultations.
- Education: Imperial College London for medicine, then a UCL master’s degree in nanotechnology and regenerative medicine (award years [to confirm]).
- Research: personalised knee replacement that respects each patient’s own anatomy, the theme of a research record that includes 18 PubMed-indexed papers.
- Teaching: faculty since 2025 on a Visiting Surgeon Programme, in which overseas surgeons observe his robotic technique, and an invited international speaker on personalised joint replacement.
Why Knee Replacements Fail, and What a Revision Can Achieve
The National Joint Registry lists the 5 commonest reasons for knee revision as loosening, infection, spreading arthritis, instability and pain. Timing differs. Infection is most likely in the first year, while loosening and pain become more common from 1 to 3 years after surgery.
A revision is harder than a first operation. Versus Arthritis says the benefits tend to lessen with each revision. The NJR found that re-revision is about 15% by 10 years, 5 times the current rate after a first total knee.
Timing of the first revision matters too. When a revision was needed within 1 year of the original operation, almost 10% needed another within a year, and about 20% by 5 years (NJR). That is why finding the exact cause comes before any decision.
Pain alone is the hardest case. Versus Arthritis says 10 to 20% of people have moderate or severe pain after a knee replacement. When there is no technical fault, another operation cannot fix it. Mr Sivaloganathan will tell you plainly if revision is unlikely to help.
Alternatives to Complex or Revision Knee Surgery
Not every troublesome replaced knee needs another operation. The NHS says physiotherapy and exercises may help a knee that is stiff, painful or unstable after replacement. Versus Arthritis notes that some hospitals run pain clinics for pain with no mechanical cause.
NICE guideline NG157 (recommendation 1.1.2) asks surgeons to discuss alternatives to joint replacement, as well as the chance of more surgery later. For a first knee with early arthritis, his knee pain management and injections page sets out non-surgical care.
Choosing not to operate is a valid decision if the knee is stable and the pain is bearable. The NHS notes that infection reaching deep into the knee may need further surgery, so ask for a review in 2026 if symptoms change.
Your Complex Knee Pathway, Step by Step: Appointment, Tests and Theatre
- Records: gather your operation notes, implant details and previous X-rays. The NJR has recorded knee replacements in England, Wales and Northern Ireland since April 2003.
- First consultation: at any of his 6 clinics in and around London, covering how the knee has behaved since your last operation, plus an examination.
- Tests: X-rays and detailed imaging to study alignment and bone quality (his site). Infection is ruled in or out first, because it changes the operation (NJR, NHS).
- Planning: a 3D plan sets implant size, any extra stems or blocks, and the alignment to aim for (his site).
- Your decision: the options, risks and chance of further surgery are talked through, as NICE NG157 (1.1.2) recommends. You choose whether and when to go ahead.
- Theatre day: a general or spinal anaesthetic, then a 1 to 2 hour operation in a typical case (his site, NHS). Physiotherapy starts the same day where possible, as NICE NG157 (1.10.1) advises.
Recovery and Risks After Complex Knee Replacement
His page says most patients stand and walk with help within 24 hours, and go home after 1 to 3 days. Complex cases can take longer to recover. Versus Arthritis notes that moving off walking aids may take longer after a more complex operation, and that gains continue for as long as 2 years.
The NHS knee replacement recovery guide advises waiting at least 6 weeks before driving after a total knee, and avoiding heavy lifting for 3 months. Your surgical team may set different limits after a revision.
Risks are higher than for a first knee. The NJR gives about 15% re-revision within 10 years, and a 0.94% chance of death within 90 days of a knee revision. Deep infection affects about 1 in 100 knee replacements, according to Versus Arthritis.
| Treatment | Hospital stay | Example risk |
|---|---|---|
| Complex first-time replacement | Usually 1 to 3 days (his site) | About 1 in 100 deep infection, as for knee replacements generally (Versus Arthritis) |
| Single-stage revision | Usually 1 to 3 days (his site) | About 15% re-revised within 10 years (NJR) |
| Revision within 1 year of the first operation | Usually 1 to 3 days (his site) | Almost 10% re-revised within 1 year, about 20% by 5 years (NJR) |
| Any knee revision | Usually 1 to 3 days (his site) | 0.94% risk of death within 90 days (NJR) |
| Two-stage revision for infection | 2 operations, each with its own stay (NJR, NHS) | Very rarely, uncontrolled infection leads to knee fusion (Versus Arthritis) |
Complex Knee Clinics and Hospitals in London
His complex robotic operations are carried out at King Edward VII’s Hospital and Chelsea Private Care. Mr Sivaloganathan holds consultations at 6 sites in London, Brentford and Harrow, listed below.
| Location | Address | Clinic times |
|---|---|---|
| King Edward VII’s Hospital | 5–10 Beaumont Street, London W1G 6AA | Wednesday, 9:30am to 12:30pm |
| Chelsea Private Care, Chelsea and Westminster Hospital | 369 Fulham Road, London SW10 9NH | Monday mornings |
| Syon Clinic | 941 Great West Road, Brentford TW8 9DU | Monday, 5:30pm to 8pm |
| Clementine Churchill Hospital | Sudbury Hill, Harrow HA1 3RX | Monday, 12pm to 2:30pm |
| Chiswick Outpatients | Bond House, 347–353 Chiswick High Road, London W4 4HS | Building open Monday to Friday, 8am to 8pm |
| The Lister Hospital | Chelsea Bridge Road, London SW1W 8RH | Building open Monday to Friday, 8am to 6pm |
Fees and Insurance for Complex Knee Surgery
There is no published 2026 fee for complex or revision surgery, as the parts needed vary from knee to knee. The practice can give you the costs once your plan is clear.
Mr Sivaloganathan sees self-paying patients and patients insured with AXA Health, Aviva, Bupa and Healix.
Covered by a different provider? Send a message through the contact form to check before booking.
FAQs About Complex and Revision Knee Replacement
Is a complex or revision knee replacement major surgery?
Yes. It is a bigger undertaking than a first replacement, and Versus Arthritis says revision surgery is more complicated. The NJR gives a 0.94% risk of death within 90 days of a knee revision.
How is a complex knee replacement different from a standard one?
A standard knee relies on your own ligaments for stability (his site). A complex knee may need longer stems, metal blocks for missing bone or a hinged design, as Versus Arthritis describes.
How long does recovery take after a revision knee replacement?
Most people stand with help within 24 hours and leave hospital in 1 to 3 days (his site). Versus Arthritis says getting off walking aids can take longer after a complex operation, and improvement continues for up to 2 years.
When can I drive after complex knee surgery?
The NHS advises at least 6 weeks after a total knee replacement, provided you can stop safely in an emergency. After a revision, Mr Sivaloganathan may advise a longer wait.
Can the problem come back after a revision?
Yes. The NJR puts re-revision at about 15% within 10 years. The risk is higher, around 20% by 5 years, when the first revision was needed within a year of the original operation.
Will I need 1 operation or 2 if my knee replacement is infected?
Often 1. The NJR found single-stage revision for infection was used twice as often as the 2-stage route over the past 5 years. Some infections still need 2 stages, and a washout keeping the implant suits some early cases.
Is there an alternative to a second knee replacement?
Sometimes. The NHS says physiotherapy and exercises may help stiffness or instability. Stiffness can also be treated by manipulation under anaesthetic, which changes no parts (Versus Arthritis).
Why does my replaced knee still hurt?
Causes include loosening, infection, instability and spreading arthritis (NJR). Versus Arthritis says 10 to 20% of people have lasting pain with no technical fault, which another operation cannot fix.
Can you revise a knee that another surgeon replaced?
Bring your operation notes, implant details and X-rays to the first visit. The NJR has records of knee replacements in England, Wales and Northern Ireland back to April 2003.
How much does a revision knee replacement cost?
Fees are not published for 2026, because each complex knee needs different parts. Ask the practice for costs once your plan is set.
Is the robotic arm used for every complex knee?
The plan is made for each knee, and the robotic arm guides the bone work where it adds value. The NJR’s robotic data so far covers first-time replacements, so ask what it offers in your case.
Book a Complex Knee Assessment with Mr Sivan Sivaloganathan
Book an assessment to find out whether robotic complex knee replacement, a smaller procedure or no operation suits your knee. Bring your operation notes, implant details, X-rays and medicines list.
- Phone: Call the practice on [to confirm] to arrange a complex knee review.
- Online: use the appointment booking form to pick a clinic, or message the team on the contact form.
His blog covers the disadvantages of knee replacement surgery, benefits, risks and recovery after a total knee and the operation step by step. All his treatments are listed on the treatments page.
Ring your GP surgery or NHS 111 the same day if a replaced knee becomes hot and swollen, a calf swells painfully or a wound leaks. For chest pain, breathlessness or possible sepsis, with signs like new confusion or blotchy skin, dial 999 or head to the nearest A&E.