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Review
. 2015 Oct;97-B(10 Suppl A):3-8.
doi: 10.1302/0301-620X.97B10.36542.

Unicompartmental knee arthroplasty: is the glass half full or half empty?

Affiliations
Review

Unicompartmental knee arthroplasty: is the glass half full or half empty?

D W Murray et al. Bone Joint J. 2015 Oct.

Erratum in

  • Errata/Corrigenda.
    Haddad FS. Haddad FS. Bone Joint J. 2015 Dec;97-B(12):1732. doi: 10.1302/0301-620X.97B7.37439e. Bone Joint J. 2015. PMID: 26637692 Free PMC article.

Abstract

There is a large amount of evidence available about the relative merits of unicompartmental and total knee arthroplasty (UKA and TKA). Based on the same evidence, different people draw different conclusions and as a result, there is great variability in the usage of UKA. The revision rate of UKA is much higher than TKA and so some surgeons conclude that UKA should not be performed. Other surgeons believe that the main reason for the high revision rate is that UKA is easy to revise and, therefore, the threshold for revision is low. They also believe that UKA has many advantages over TKA such as a faster recovery, lower morbidity and mortality and better function. They therefore conclude that UKA should be undertaken whenever appropriate. The solution to this argument is to minimise the revision rate of UKA, thereby addressing the main disadvantage of UKA. The evidence suggests that this will be achieved if surgeons use UKA for at least 20% of their knee arthroplasties and use implants that are appropriate for these broad indications.

Keywords: unicompartmental knee replacement; unicompartmental knee arthroplasty.

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Figures

Fig. 1
Fig. 1
Graph showing the Kaplan-Meier survival of unicompartmental and total knee arthroplasty (UKA and TKA) based on data from the National Joint Registry., CI, confidence interval.
Fig. 2
Fig. 2
Funnel plot taken from the National Joint Registry for all knee arthroplasties combined for an example surgeon who is an outlier. His knee arthroplasty practice includes a large proportion of unicompartmental knee arthroplasties.
Fig. 3
Fig. 3
Graph showing the percentage of unicompartmental and total knee arthroplasties (UKA and TKA) having poor, fair, good and excellent outcomes according to the Oxford knee score based on data from the New Zealand Joint Registry.
Fig. 4
Fig. 4
Graph showing the two-year revision rates for unicompartmental and total knee arthroplasty (UKA and TKA) having different Oxford knee score (OKS) categories at six months post-surgery, based on data from the New Zealand Joint Registry.
Figs. 5a - 5b
Figs. 5a - 5b
Funnel plots for a) total knee arthroplasty and b) unicompartmental knee arthroplasty for a surgeon who is an outlier for all knee arthroplasties combined (Fig. 2).
Figs. 5a - 5b
Figs. 5a - 5b
Funnel plots for a) total knee arthroplasty and b) unicompartmental knee arthroplasty for a surgeon who is an outlier for all knee arthroplasties combined (Fig. 2).
Fig. 6
Fig. 6
Graph showing the relationship for the Oxford unicompartmental knee arthroplasty (UKA) between revision rate (revisions per 100 component years) and usage of UKA (the percentage of a surgeon’s knee arthroplasties that are UKA), based on data from the National Joint Registry.

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