Blog category: Research

The Conformis iTotal custom-made knee – the very best knee prosthesis on the market!

Great news – the 20th annual report of the National Joint Register has recently been published, and this shows that the Conformis iTotal custom-made knee replacement prosthesis gives the best 10-year results of any knee prosthesis on the market, with the lowest revision rates!

The 10-year revision rates for the Conformis iTotal prosthesis are 1.23%, compared to the average figure for all types of knee prosthesis of approximately  5% – which equates to an over 75% reduction in the risk of revision!


Robotic-assisted knee replacement surgery: nothing more than just a marketing scam?

Hot off the heels of the Conformis custom-made knee replacement prosthesis being shown in the latest National Joint Register to have the best results ever recorded for 10-year prosthetic survivorship figures…

… further research demonstrates that bog-standard off-the-shelf knee replacement prostheses implanted by robot-assisted surgery gives no improvement in patient outcomes, in terms of clinical scores.

In this study by researchers in Turkey, the surgeons compared the outcomes of 70 patients undergoing robot-assisted knee replacement surgery to 46 patients undergoing standard ‘manual’ surgery. They looked at the Knee Injury and Osteoarthritis Outcome Score (KOOS), the Oxford score, a Visual Analog Scale pain and satisfaction score, and the Forgotten Joint Score. What the researchers found at 2-year follow-up was no difference whatsoever in any of the above outcomes. CLICK HERE to read more.

i.e. Further evidence that robot-assisted knee replacement surgery is nothing more than a very expensive marketing scam!

This fits in with the most recent data from The American Joint Replacement Register, which shows that robotic knee replacement does not give any improvement in the common causes of early revision surgery, such as malalignment, malposition, stiffness, pain or instability: CLICK HERE to read more.

In fairness, computer navigated surgery and robot-assisted knee replacement surgery have been shown to give better alignment of a knee prosthesis when viewed with X-rays (i.e. it helps a surgeon put the prosthesis in straighter). However, this seems to be irrelevant in terms of what actually matters to the patient, which is clinical outcomes, in terms of patient satisfaction rates, function and long-term prosthetic survivorship figures.

Furthermore, when a Conformis custom-made knee replacement is performed, 3D-printed custom-made patient-specific cutting blocks are manufactured for each individual patient, so that the bone cuts are made as close to perfect as possible, and research has shown that this gives prosthetic alignment that is equally as accurate as computer navigated or robot-assisted knees. The advantage of the Conformis knee, however, is that the prosthesis itself is custom-made, meaning that it fits pretty much perfectly to each individual patient’s knee, every time, no matter what the size, shape or contours of that patient’s knee might be. With robot-assisted knee replacements, on the other hand, the prosthesis may be put in accurately… but the prosthesis itself is a standard off-the-shelf prothesis that may or may not match the natural native geometry of the patient’s own degree, and hence there is far less of a guarantee that the patient well end up with a knee that feels ‘right’ to them. This is why patient satisfaction rates with a custom-made Conformis knee have been shown to be 90 to 95%, compared to just 80 to 85% for a standard off-the-shelf knee (which includes those knees used for robot-assisted knee replacement surgery).

Conformis custom-made knees: designed to fit each individual patient’s knee perfectly.

The above is not really ‘news’, because large long-term studies have already shown us quite clearly that robotic knee replacement surgery is pointless. Indeed, in a massive study from South Korea, where the researchers compared outcomes from 700 robotic-assisted knee replacements to 700 standard knee replacements, with a 10-year follow-up, the authors found no differences between robotic-assisted knee replacement and conventional knee replacement surgery in terms of functional outcome scores, aseptic loosening, overall survivorship and complications. The authors concluded that “Considering the additional time and expense associated with robotic-assisted TKA, we cannot recommend its widespread use.”  CLICK HERE to read more.

So, what, in our opinion (an opinion that is strongly supported by the published scientific evidence) is the best type of knee replacement to have if you need knee replacement surgery:

a Conformis custom-made knee!

  • CLICK HERE to read more about Conformis knees having the lowest 10-year revision rate of any prosthesis on the market
  • CLICK HERE to find out more about Conformis knees


Latest research confirms that surgeons do have a lower threshold for going ahead with revision surgery for patients with partial knee replacements compared to totals.

“A lower threshold for revision of aseptic unicompartmental vs total knee arthroplasty”
William B. Johnson, Jr., C. Anderson Engh, Jr., Nancy L. Parks, William G. Hamilton, P. Henry Ho, Kevin B. Fricka
The Bone and Joint Journal 2020; 102-B(6): 91-95

Research out of Alexandria, Virginia, USA has confirmed what many of us have suspected for a long time…

In this study of 619 cases of revision knee arthroplasty, those patients undergoing revision of a partial knee replacement had a significantly higher Oxford Knee Score than similar patients undergoing revision of total knee replacements… i.e. the partial knee replacement patients were being revised despite having less symptoms (i.e. with better knees) compared to the total knee replacement patients.

Revision knee replacement is easier when revising a partial knee replacement compared to a total; therefore, surgeons tend to have a lower threshold for going ahead with revision surgery in patients who are having issues with loosening/failure of a partial knee replacement, compared to patients suffering similarly bad issues with a total knee replacement. This is just one of the factors that helps explain why we tend to see a higher revision rate with partial knee replacements compared to totals. This does not, however, mean that partial knee replacements (when done for the right reasons in the right patient at the right time) are ‘worse’ than total knee replacements.

This study also showed that of the partial knee replacements that were revised, 36% were revised for aseptic loosening and 36% were revised for progression of osteoarthritis into the non-resurfaced compartment(s).

CLICK HERE to read the article


Robotic knee surgery shown to be a pointless marketing sham!

“Does Robotic-assisted TKA Result in Better Outcome Scores or Long-Term Survivorship Than Conventional TKA? A Randomized, Controlled Trial.”
Young-Hoo et al.
Clinical Orthopaedics and Related Research Feb 2020; 478(2): 266-275

Researchers from South Korea have published a Level 1 (the highest possible quality) study with long-term (10-year!) outcomes investigating the use of robotics for knee replacement surgery. In this study about 700 knee replacement procedures performed robotically were compared to about 700 ‘routine’ knee replacements, with patients being followed up prospectively and with clinical and radiological outcomes being evaluated.

The authors found no differences between robotic-assisted knee replacement and conventional knee replacement surgery in terms of functional outcome scores, aseptic loosening, overall survivorship and complications. The authors conclude that “Considering the additional time and expense associated with robotic-assisted TKA, we cannot recommend its widespread use.”

CLICK HERE to read more

Latest study shows that steroid injections actually INCREASE the future risk of knee replacement surgery.

Increasingly, the latest evidence has suggested that steroid (corticosteroid) injections into joints may reduce pain and symptoms in the short-term, but that they can actually cause increased damage inside the joint and end up causing more harm than good in the longer-term.

A study from a team at The Radboud University Medical Centre, in Nijmegen, the Netherlands, has recently been published in the May edition of The Bone & Joint Journal. In this study the authors looked back over the cases of nearly 4000 patients with osteoarthritis of the knee, or at risk of OA, with a 9-year follow-up period. The researchers found that each injection of steroid increased the risk of future knee replacement surgery by 9.4%.

So, roughly speaking, injecting a symptomatic ‘at-risk’/degenerate/arthritic knee increases the risk of actual knee replacement surgery within roughly 10 years by roughly 10%!!  — something to really bear in mind when deciding whether or not to have steroid injected into your knee!

CLICK HERE for further details about the study