Custom Conformis Knee Replacement

This is the best knee replacement available in my view, stemming from personal observations, published studies and some 17 years of experience!

The design features are simply unmatched, the technologogy delivers what it promises - a knee that fits precisely and moves vitrually identically to a normal knee. Also because of the way it is based on the scan the leg ends up straight with minimal variation.

Cost is £13900 all inclusive package (plus CT scan and an initial consultation), available under insurance companies some of which actively promote it.

Custom Total Knee Replacement in the media:

Article in the Mirror Newspaper re bilateral custom knee replacement, Sussex, UK

ITV News

Saga Magazine

FAQs Custom TKR

I have now carried out over 217 Custom Total Knee Replacements, and I am convinved it is the Best Knee Replacement giving predicable, reliable outcomes of rapid recovery, strength, a knee that feels like ones own, overall satisfaction, trust, and restoration of quality of life.

A recent London's Patient's physiotherapist described the recovery at 4 weeks as "Exceptional".

A visiting surgeon described what he saw as "it was very impressive procedure"

Patient feed back: Please see some patient reviews at the I want Great Care site, here

Conformis Total Knee replacement is available by Mr Lewis in Wimbledon at Wimbledon Parkside Hospital or in Sussex at Goring Hall Hospital

Reasonably new (2007) and exciting alternative for the treatment of knee arthritis.

  • An alternative to traditional knee replacement
  • Feels like your own knee 
  • A true custom, bespoke knee cobalt chrome alloy implant manufactured on a patient-by-patient basis from thier CT scans so that it exactly fits that patients knee. Technology delivering results.

Video Explaining the 3D printing of the individual positioning guides to allow precise implantation of the custom made implant:

March 2017 2 week recovery - showing some advances in care leading to radid recovery.

Early Recovery from Custom Total Knee Replacement (iTotal by ConforMIS)

Another video showin 12-14 day recovery from Custom Total Knee (iTotal by Conformis- surgery J Lewis)

1 year follow up custom Total Knee showing strength and confidence in the knee (iTotal - surgery J Lewis)

8 week and 3 month follow up iTotal (Male patients - both had extreme arthritis)

Video shows a Partial knee resurafcing  (known as the iUni by conformis) Uni = One compartment.

Video shows design details of a custom Total Knee Replacement (known as the iTotal by Conformis)

A resurfacing implant. Due to design improvements it is only 4mm thick meaning it is used to recoat the end of the thighbone, a resurfacing custom knee implant in the weight-bearing zone. Traditional knee replacements require the sawing of approximately 8-9mm of the end of the thighbone to accommodate the thicker traditional knee replacement, wheras the new design replaces the articular cartilage thickness.

Custom knee replacement is a quantum leap in technology for knee resurfacing and replacement implants.

The manufacture time for a custom knee replacement is only 5 weeks.

The cost is £3000 more than a traditional knee replacement.

The metallic components are a cobalt chrome alloy, the same material used in traditional total knee replacements.

New technology. The first patient specific custom knees from Conformis were implanted in UK in 2012 after development in the USA since 2002.

Three custom knee options are available

  • Partial knee resurfacing (replacement)  (Conformis iUni)
  • Two thirds knee or "Conformis iDuo"- meaning two compartments out of the three that are in the knee
  • Total knee replacement (Conformis iTotal)


Three further patients at day 12 to week 6 following iDuo (2/3rd resurfacing, ligaments all retained)

Getting your Custom Knee - the 6 week process

  1. Consultation with a trained specialist.
  2. CT scan (to a specific protocol), images transferred to the USA.
  3. Engineers reformat the CT into a 3D model of that knee and extract the surface topography
  4. Implant manufactured and shipped along with patient specific implant positioning guides
  5. Surgery and recovery.
  6. Early outcomes promising, "feels like a normal knee"

Talking to USA surgeons with experience of over a 100 cases for a given surgeon, and the initial UK surgeons the early results are very encouraging.

Some early observations are that the new knee feels like a normal knee, moves like a normal knee and does not click or clunk. Pain relief is very good. One patient on being asked does it feel like you own knee replied "absolutely"- and at only 6 weeks post- surgery (Duo).

The design team are of the highest pedigree and the development process has been drawn out and exacting before release. However it is a new productand therefore does not have a long term track record and thus this aspect must be understood and balanced with the potential benefits

FAQs:  Conformis Total Knee Replacement (iTotal) FAQs

What are the main advantages?

It gives a knee that feels like your own and restores quality of life.

This has been reported at national meetings in scientific studies and, as an Orthopaedic Surgeon, has been my experience. The study presented at the British Association for Knee Surgery reported that 100% of patients felt as if it were their own knee. Specifically 61% felt it was their own knee all of the time and 39% at least some of the time. Comments from patients include:

"It feels like my young knee"

"It feels like my own, always has" (since the operation) 

“I forget about it”

“The strange thing is that it feels like my own knee”

It is also highly rated for its feeling of stability.

Is it available on the NHS?

No, unfortunately not although this may change in the future. For patients in Germany the German public health system fund it, presumably because they see the benefits, hopefully the same thinking will follow in the UK.

How much more expensive is it than an off the shelf total knee replacement?

It’s £3,000 more, but this also includes custom 3D printed positioning guides which, on their own, for an off the shelf total knee replacement are approximately £500. Furthermore the length of hospital stay is reduced by one day so the real cost is actually £2,000 more. 

Financial details

In reality NHS patients are unable to pay a "top-up" because of the NHS principle of healthcare being free at the point of use.

Insured patients are covered for the cost of knee replacement surgery worked out on the basis of an off the shelf knee, therefore the Hospital will ask patients to pay a £3,000 top up - on top of insurance cover- for a custom knee, so this might not be for everyone.

Self-paying patients would pay an "all inclusive package price" of £10,680 plus £725 for a CT scan, £100 for an x-ray and £150 for a consultation.

An off the shelf knee replacement (best in class for survivorship at 10 years national joint registry) "all inclusive package price" is £8,160 and, £100 for an x-ray £150 for an initial consultation.

How long does it take?   

It usually takes 5.5 weeks from initial consultation to surgery. A consultation is available within 1 week, and a CT scan can be done on the day of consultation if on a Thursday or Friday. Scans are then electronically uploaded to Burlington, Massachusetts, USA. The new custom knee and positioning guides arrive at Goring Hall in sterile condition 4.5 weeks later.

What’s special about Goring Hall Hospital?

The key strengths at Goring Hall are:

  • Teamwork, its people, attention to detail, private single rooms, clean fresh air at its sea-side location, extensive experience and a special focus on a retirement population.
  • Energy for continual innovation and an award winning enhanced recovery programme.
  • Excellent state-of-the-art anaesthesia, and some world leading surgical strengths. 

In short the product of drive, focus, location, people and compassion. 

We offer an all-inclusive package

A truly transparent package with no hidden costs:

  • The only extra costs would be the cost of making landline calls from patients’ rooms, alcoholic beverages, or a meal ordered for a visiting guest.
  • The purchase of Physicool bandaging fluid is optional at £16.65 per bottle or 3 for £50 which is usually adequate; the bandage itself is supplied.

Specifically it includes:

  • Pre-assessment
  • Surgeon and Anaesthetic fees
  • Prosthesis fees
  • All nursing / physician / theatre costs / hospital costs/ all medicines including post discharge medication for 2 weeks
  • 6 sessions of physiotherapy post-discharge (local to you for your convenience and guided by us)
  • Any walking aids or "gadgets" as required
  • Unlimited follow up as required with Mr. Lewis
  • 1 month of insurance to cover any unexpected problems relating to care. If this were the case, you would be covered for further care at Goring Hall. 

Overview of Risks

Medical case law requires a reasonable time to weigh information and all the risks to be understood.

This avoids the situation whereby one says "I wouldn't have had it had I known”.

As a result this can lead to a long list of risks, which is not because the treatment isn't effective; it is because of current case law.

Risks can be categorised as Medical Risks and Knee Risks.

Medical Risks

These include death, stroke, heart problems, chest infection, bladder or urinary problems and nerve injury from the anaesthetic. However, risk prevention and fitness optimisation are key components of care. A short-term (8 hours) urine catheter is commonly used post-surgery in male patients.  

Patients who are slimmer and fitter are considered to be less at risk of these events. The Hospital and anaesthesia team are experienced in looking after patients on Warfarin, with high blood pressure and many other medical conditions.

Blood transfusion:

Mr. Lewis works at avoidance level and audit data demonstrates a 0% transfusion rate for knee surgery.

Knee Risks

The risk of infection is (0.25%). Fortunately, Thrombosis is now fairly rare due to prevention strategies, which include walking the same day, calf pumps, anticoagulants (tablets- Apixaban) as per national guidelines. Wound problems are also rare. Turning to stiffness - the need for bending under anaesthesia as a second procedure (1%), fracture - rare, component failure - rare, inability to kneel - 10%, the need for further surgery in the short term (1 %) . Soft tissue discomfort - sometimes if the knee hasn't been straight for a while, when it is straightened the hamstrings can then be stretched a little and this can cause pain; this is often treated with an injection of cortisone.

Long term wear or failure 

This risk should be emphasised. As a relatively new product (2007) the long term results are not known, however the wear simulator studies are impressive with wear rates 40x less than standard implant quality polyethylene. All implants are entered into the National Joint Registry for monitoring, and this entry process in itself is also audited. However there have been situations in the past where simulator studies have turned out not to detect a design problem with a given implant.

Ultimately there will always be associated risks with a new or recent product. Patients have a choice between old technology and old design principles along with the accompanying long-term data or a new or recent product with up-to-date design but limited long-term data.

The PFC cruciate retaining knee, which is best in-class for survivorship at 10 years (NJR data) gives a good quality off-the-shelf knee replacement and is the UK’s most widely used knee replacement as chosen by surgeons.

In summary surgery is not risk free, however the team works strenuously to minimise risk at every level. The decision to proceed is always a joint one after considering the alternatives. 


Mr. Lewis has given lectures on his Conformis experience, outcomes and design aspects in the USA, India and the UK.  Mr. Lewis has a Masters degree in Orthopaedic Engineering.

The combination of his background, special area of interest and the extensive time that he has spent with the design engineer understanding the intricacies of the product make him the leading surgeon in the UK offering this type of custom knee replacement procedure (defined by infection-free numbers of procedures).


Mr. Lewis has been fortunate to have had patients choose to come from overseas, including Dubai, and as north in the UK as Middlesborough for custom knee surgery as well as Luxembourg, Ireland, and Holland for other surgeries.

Patient Testimonials:

Mr. Lewis,
I have just enjoyed my first ski trip following my custom knee resurfacing seven months ago. I am delighted to report that the knee performed flawlessly with no pain or swelling whatsoever.

Thank you once again for such an excellent result, I will be glad to refer patients to you for this procedure if required.

Kind Regards,

Dr Douglas Ferguson


I have been involved in sport all my life and physical fitness has been one of my passions. In recent years I have had to give up many of the activities that gave me so much pleasure due to pain in my knees.

I was advised that I needed a knee replacement a few years ago, but was unwilling to undergo the surgery that was commonly available. I have been searching the internet looking for something different. Early this year I came across the Conformis system of custom made knee surgery. I discovered that one of the few surgeons experienced in this method was Mr. James Lewis, based in Worthing, Sussex. I took the plunge and had the surgery performed some three months ago.

I have been extremely happy with the results and even at this early stage I am able to resume activities I have not attempted for the past 10 years, like tough mountain biking, jogging, tennis and weight training.

I cannot speak highly enough of James Lewis and his team at the Sussex Orthopaedic Clinic and I consider Conformis to be the Rolls Royce of knee replacements.

David Pike.

Hello James
I recently returned from a week at Kicking Horse Mountain Resort, BC, rated by Powder magazine as one of the five most challenging ski areas in North America.  I am pleased to say the knee responded brilliantly; no pain, discomfort or swelling.  I did catch the inside edge of my right ski a couple of times on day one. I put this down to the fact that pre op I was slightly bow legged, but after the operation I was back in true alignment.  Once I had made a small mental recalibration to my technique, I was able to once again really enjoy the steep and deep, with confidence.

Thank you for performing my iDuo knee surgical procedure with such expertise.

Infection rate: 0%

Thrombosis rate: 0%

Transfusion rate: 0%

MUA rate for custom Total Knee Replacement: 0%

Written 20 /02/2015 by James Lewis

PDF of Conformis Total Knee Replacement Below

Knee Weblinks of interest

Conformis (manufacturer) website.