Once, partial knee replacements were deemed suitable for just 5-10% of all knee replacement patients. Today, some put that figure closer to 50%. Nick London explains what’s behind such an enormous change.
With any procedure, especially a new one, managing risk is vital. That’s why, in the early days of partial knee replacements, groups of patients thought to have been at increased risk were filtered out. It was a substantial list which avoided heavier patients, active patients, patients with any wear in the kneecap or with cruciate ligament-deficient knees. Selection also maintained a narrow age range (not too young in case the implant wore out, not too old because of the surgical risk). By the time all those elements had been factored in, out of all patients deemed suitable for a total knee replacement, only 5-10% were believed suitable for a partial.
In a sort of medical chicken and egg scenario, the relative rarity of partial knee replacements meant few training opportunities for junior doctors and consultants. Some facilities specialised in partial knees and a lucky few surgeons got the exposure and experience they needed. Others didn’t see very many at all. So even as criteria began to relax, growth in partial knee replacement surgery remained subdued as there wasn’t the breadth of expertise to carry it out.
Over the past decade however, two important things have changed.
Expanding the pool of suitable patients
There’s now clear evidence (some national, some gathered by our own knee surgeons) that most patients with severe wear behind the kneecap are not only suitable candidates for partial knee replacement but that they will be better served by it. The same is true for many patients with ACL-deficient knees, and also for a wider age range of patients, from 40 to 90+. Not every patient in these categories will be suitable for a partial knee but the general expansion of selection criteria has changed the proportion of suitable patients to 20% in most surgeons’ eyes, and to 40-50% in the opinion of some.
NICE emphasis on partial knee replacement
The other major change, which happened only recently, was a shift in National Institute for Health and Care Excellence (NICE) recommendations. It is now a requirement for surgeons to offer both partial and total knee replacements to patients who are suitable for either. This is a significant shift because it means every patient suitable for a partial replacement must at least have a discussion about it. It encourages surgeons to explain, educate and give patients a choice. The shift has further highlighted a need for more surgeon training and some surgeons may now need to refer patients on if that’s not where their experience lies.
It was in light of the change in NICE guidelines, and as staunch advocates of partial knee replacement, that the four Yorkshire Knee Clinic surgeons were asked to explain what we believe are the right patient selection criteria and surgical technique for partial knee replacement. You can find more about that here.
The Yorkshire Knee Clinic philosophy has remained clear for several years: whilst excellent results can be achieved with total knee replacement, we believe that partial knee replacement (resurfacing) surgery delivers better patient outcomes with reduced surgical risk for most patients who are deemed suitable compared to total knee replacement. We also believe strongly in fixed-bearing partial knee implants, which are showing excellent longevity and for which the chances of requiring revision (re-do) surgery are becoming similar to that of total knee surgery. To put it simply – the benefits far outweigh the risks in our opinion.
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