Partial knee replacement could be first choice for some patients with osteoarthritisBMJ 2019; 367 doi: https://doi.org/10.1136/bmj.l5994 (Published 30 December 2019) Cite this as: BMJ 2019;367:l5994
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I personally agree a partial knee replacement (PKR) is an excellent option for some patients with limited knee arthritis, when performed by an appropriate surgeon, in a suitable facility. However, is it me, or is there a fundamental issue missing in this National Institute for Health Research (NIHR) assessment of the original publication by Beard et al?
The quote is; ...'The proportion of people who had a re-operation was similar in both groups'. This is the assessment at only 5 years. NIHR suggest that the partial knee replacement is more cost effective and better in terms of quality adjusted life years, within this time frame.
However, this seems to be a very short term view, and in contrast to registry data. I am concerned that data seen in the 2019 National Joint Registry (NJR) annual report shows in figure 3.2 (c) the revision rate for partial knee replacement (fixed bearing, apparently better than mobile bearing) to be over 5% at 5 years and very nearly 10% at 10 years. This is in obvious contrast to total knee replacement (TKR) where figure 3.2 (a) shows a revision rate at 2% at 5 years and 3% at 10 years, for fixed bearing TKR, the most common TKR.
This is a very complex issue as illustrated when the 'threshold' for revision in (PKR) may often be lower than for TKR. Also the paper deals with only medial osteoarthritis and not the more difficult and less often treated with PKR , lateral compartment osteoarthritis. However, statistically, as those that have symptomatic osteoarthritis in one compartment of the knee a proportion will ultimately develop intolerable symptoms from osteoarthritis in another compartment.
Therefore both the patient and surgeon still have a difficult decision to make when a knee and health economy may benefit from a PKR in the short term but at the cost of longer term hazard of requiring revision than would have been required if a TKR had been performed in the first place.
Essentially the NIHR assessment of this research doesn't yet give enough evidence, in practise, to support the difficult decision making process for the patient and surgeon, at the moment, when a PKR may be an option.
Competing interests: No competing interests