According to the latest data, of all the knee replacements carried out at the Harrogate and District Foundation Trust, 32% are partial knee replacements. Yet across Yorkshire and the North East as a whole, the proportion is just 7.2%. So why are some NHS trusts performing so many more partial knee replacements than others? Nick London explains.
We’ve written at length about the benefits of partial knee arthroplasty (replacement), but just in case you’re new to these pages, a quick recap. As a knee succumbs to osteoarthritis, a knee replacement may be the eventual solution. Your knee has three compartments and where more than one of these is affected by osteoarthritis a total knee replacement may be the natural choice. Where just one compartment is severely affected, however, a partial knee replacement could be the answer, and for a number of reasons.
The 2020 NICE guidelines mandate surgeons to offer partial as well as total knee replacements for suitable patients. Multiple national joint registries and patient outcome reports published by numerous groups worldwide show that revision rates at ten years for partial replacements are low and now very close to those of total knee replacements. Surgical time is less. Hospital stays and complication rates are reduced. Recovery rates are swifter and patients are more likely to ‘forget’ they’ve had a partial knee replacement than is the case with a full.
There is, frankly, a huge body of evidence built over the past decade to support partial knees, so it’s with some astonishment that myself, Dave Duffy, Jim Newman and other high volume partial knee replacement surgeons find that there are some centres in the country performing zero or close to zero of them.
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The partial knee postcode lottery
I am indebted to Cambridge orthopaedic surgeon James Gill for sharing data at the recent Bristol and Oxford Uni Knee Meeting (2022) which showed the percentages of partial knees performed in each hospital and region. Our own ‘patch’ was third nationally with 32% with the highest at 55% – reaffirming my view that partial knee replacements are appropriate for a majority of patients.
The comparisons with regional averages (let alone individual trusts) are stark. In Yorkshire and the North East, an average of just 7.2% of knee replacements are partials. In the North West it’s just 6%. No region in England, Wales or Northern Ireland managed better than 11.4% (the South West). The Isle of Man didn’t do any at all.
The term ‘postcode lottery’ is an overly used phrase, but it’s hard to think of a better application of it. So why is this happening?
The partial problem
Technical difficulty: There is a view that getting good results from a partial knee replacement is technically more difficult than for a total replacement. In my opinion, with the best, contemporary fixed bearing partial knees, that simply isn’t true but it may go some way to explaining why even some experienced knee surgeons haven’t done significant numbers of them.
Surgeon training: It’s certainly true that surgeons often don’t see many partial knees during training. This is likely to remain the case unless implant companies and those of us who do significant numbers of partial replacements do more in terms of surgeon education and training.
Historical bias: In the early days of partial knee replacements, revision rates were considerably higher than they are now, and around three times that of total knee replacements at ten years. For the best performing contemporary, fixed bearing partial knees, however, the revision rate is now very close to that of a total knee replacement, with the marginal difference heavily outweighed by all the other advantages.
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Patient Selection: In our opinion, a large proportion of all knee replacement patients are suitable for partial knee surgery. In recent years many studies (our own included) have confirmed that many pre-existing exclusions for partial knee surgery are not appropriate. We have helped demonstrate that patients of any knee replacement age (approx. 40-100) are good candidates. In the commonest partial knee replacement operation – medial (inner) compartment – most patients with severe patella-femoral (knee cap) arthritis or cruciate ligament deficiency are suitable for pure medial partial knee replacement. Surgeons performing small numbers of partial knee surgeries will often hunt for the ‘perfect’ patient whilst continuing to perform total knee replacement on many who are entirely suitable and could benefit from the reduced surgical risk and better outcomes offered by partial knees.
Frustratingly, some surgeons continue to look at historic figures rather than contemporary National Joint Registry data and use that as justification either for not training and offering partial knee replacement, or for not referring their patients to surgeons or centres which do. Such attitudes are doing an enormous disservice to knee arthroplasty patients worldwide, but particularly in the UK.
Taking our eye off the ball
We should have been training more surgeons in partial knee techniques. Clearly, we’ve faced some enormous challenges recently that would have made that extremely difficult, but this is a problem that existed long before Covid. I believe we have depended on the industry to make things right, but too many of our institutions and device companies have become hypnotized by the recent “robot wars”.
Their investment of billions of dollars in trying to out-robot each other has come at the huge and almost unforgivable expense of training. Our medical device companies were once extremely good at supporting trainee surgeons and developing experienced surgeons in applying new techniques and using new implants. Those local, regional, national and international training meetings have lost focus (or rather, they have refocused and become obsessed with assistive technology). My view is that they have substantially neglected their responsibility to help train surgeons. Until they put that right, I believe it is for those of us who are fortunate enough to have gained experience in partial knee surgery to work together, locally and more widely, to offer training and/or meetings.
Yorkshire Knee Clinic’s surgeons are taking a stand on this issue, and we’ll share more details over the coming months.
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Prof. Nick London
Private appointments weekly at The Duchy Hospital Harrogate & Nuffield Hospital Leeds
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