The effect of surgical factors on early patient-reported outcome measures (PROMS) following total knee replacement

P. N. Baker, D. J. Deehan, D. Lees, S. Jameson, P. J. Avery, P. J. Gregg, M. R. Reed


Patient-reported outcome measures (PROMs) are increasingly being used to assess functional outcome and patient satisfaction. They provide a framework for comparisons between surgical units, and individual surgeons for benchmarking and financial remuneration. Better performance may bring the reward of more customers as patients and commissioners seek out high performers for their elective procedures. Using National Joint Registry (NJR) data linked to PROMs we identified 22 691 primary total knee replacements (TKRs) undertaken for osteoarthritis in England and Wales between August 2008 and February 2011, and identified the surgical factors that influenced the improvements in the Oxford knee score (OKS) and EuroQol-5D (EQ-5D) assessment using multiple regression analysis. After correction for patient factors the only surgical factors that influenced PROMs were implant brand and hospital type (both p < 0.001). However, the effects of surgical factors upon the PROMs were modest compared with patient factors. For both the OKS and the EQ-5D the most important factors influencing the improvement in PROMs were the corresponding pre-operative score and the patient’s general health status. Despite having only a small effect on PROMs, this study has shown that both implant brand and hospital type do influence reported subjective functional scores following TKR. In the current climate of financial austerity, proposed performance-based remuneration and wider patient choice, it would seem unwise to ignore these effects and the influence of a range of additional patient factors.


  • We thank the patients and staff of all the hospitals in England and Wales who have contributed data to the National Joint Registry. We are grateful to the Healthcare Quality Improvement Partnership (HQIP), the NJR steering committee and the staff at the NJR centre for facilitating this work. This work was funded by a fellowship from the National Joint Registry. The authors have conformed to the NJR’s standard protocol for data access and publication.

    The views expressed represent those of the authors and do not necessarily reflect those of the National Joint Registry Steering committee or the Health Quality Improvement Partnership (HQIP), who do not vouch for how the information is presented. No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article.

  • Supplementary material. A further opinion by Mr M. Dunbar is available with the electronic version of this article on our website at

  • Received November 24, 2011.
  • Accepted April 3, 2012.
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