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Publication, Part of

Finalised Patient Reported Outcome Measures (PROMs) in England for Hip & Knee Replacements, April 2018 – March 2019

Official statistics
Publication Date:
Geographic Coverage:
Geographical Granularity:
Country, Strategic Health Authorities, Hospital Trusts, Primary Care Trusts, Independent Sector Health Care Providers, Clinical Commissioning Groups, NHS Trusts, Primary Care Organisations, County, Care Trusts, Hospital and Community Health Services
Date Range:
01 Apr 2018 to 31 Mar 2019



From April 2009 onwards, patients undergoing elective inpatient surgical procedures for hip replacement and knee replacement have been invited to complete pre- and post-operative questionnaires on their general and condition-specific health. Patient participation in PROMs is on a voluntary basis.

Responses to these questionnaires are analysed to assess the outcomes of the surgical procedures based on patients’ self-reported health.

PROMs publications and data can be used by patients to inform their choice of hospital provider and are used to by hospital clinicians to inform decisions about individual patients’ direct care. The data have also been used in medical research studies to improve outcomes by comparing scores across different types of treatments.

The reporting schedule for the PROMs publications has been changed which now means the finalised full-year data will be published six months earlier. Previously published in August, this will now be February. This publication is the second finalised publication released in line with the new schedule.

This decision was made due to address reporting needs amongst key users of the data for calculating more-timely finalised PROMS data. From reviewing the life cycle of historical PROMS data, we can see the majority of records have been received and processed by six months after the first full-year provisional data is released, with little variation seen in the calculated national rates after that point.


Analysis in this report is based on:

  • Pre-operative patient questionnaires completed between 1 April 2018 and 31 March 2019 and any associated in-patient hospital episodes and post-operative questionnaires;
  • Episodes of inpatient hospital care where the episode started between 1 April 2018 and 31 March 2019 and included a PROMs-eligible surgical procedure (hip or knee replacement) and any associated pre- and post-operative questionnaires. A small number of episodes recorded more than one eligible procedure; each procedure is treated independently for purposes of analysis. 
  • The data source of these episodes is the Hospital Episode Statistics data warehouse (‘HES’) , where possible, PROMs questionnaires have been linked to records of hospital inpatient activity in order to deliver a richer dataset for analysis and to provide key variables necessary for casemix adjustment.

Patient Questionnaires and Measures

Condition-specific measures

Patients receiving hip or knee replacements are asked to complete questions that are specifically tailored to their condition:

  • The Oxford Hip Score (OHS) 
  • The Oxford Knee Score (OKS) 
General health measures

All patients are also asked to complete two general measures, the EQ-5DTM Index and the EQ VAS, both before and after their surgery:

EQ-5DTM Index is a five item measure that asks patients about their:

  • ability to pursue their usual activities;
  • current experience of anxiety and/or depression, if any;
  • current experience of pain and discomfort, if any; 
  • mobility, and;
  • ability to wash and dress themselves (self-care). 

EQ – Visual Analogue Scale (EQ VAS) is a single-item ‘thermometer’-style measure which asks patients to rate their general health at the time of completion on a linear scale from 0 to 100, with 100 representing the best possible state of health.

Within their post-operative questionnaires, all patients are also asked:

  • how they would describe the results of their operation (satisfaction), and; 
  • how their problems are now, compared with before the operation (success).

Documents included in this publication

This publication includes:

  • Summary Tables
  • Data Quality Tables
  • Interactive Power BI report 
  • Interactive Score comparison tool 
  • CSV Data Pack (with footnotes)
Changes to the publication format

To improve the offering to users of PROMS data this statistical release includes an interactive Power BI report enabling them greater flexibility in querying the published data. This now includes the following information and charts that were previously published as part of the Annual Report in PDF format. 

This publication is the first of this series to be published in HTML format. This means that the charts and tables that were previously found in the PDF report are now found on the publication webpage The underlying data for the charts in the report and in the Power BI report can be found in the “Summary Tables” file.

The Data Quality Note has also been added to the HTML report, while the data quality related tables can be found in tbe “Data Quality Tables” file.

More information about the where you can find specific information from the previous format is given below:

  • Average health gain for each questionnaire – HTML report and Summary Tables
  • Improvement rates for each questionnaire – HTML report and Summary Tables
  • Further surgery and complications – Summary Tables
  • Surgical success and satisfaction – HTML report and Summary Tables
  • Most severe pre- and post-operative scores for Oxford questionnaires – Summary Tables
  • National participaton and linkage rates – Data Quality Tables
  • Provisional releases cumulative data – Data Quality Tables

Modelled Records

PROMs scores are adjusted using statistical models which account for the fact that each provider organisation deals with patients of differing complexity or casemix. Some hospitals may treat older, sicker patients and others may be specialist centres that can take patients with more complex conditions than can be treated at a general hospital. 

Casemix adjustment allows for fair comparison between providers and England as a whole. In effect it estimates the score an organisation would have if it treated a population with the same complexity as the national average.

In order for the casemix adjustment to be calculated, certain criteria must be met. Where this criteria is met, the record is called a “modelled record”. The pre-operative and post-operative questionnaire must link together and be complete. They must also be linked to an episode from the HES data set as well as having some complete fields (e.g. IMD) for the episode. More information about the casemux adjustment can be found in the PROMs Methodology document here

Further Information

PROMs Guide

For more details on the background to the PROMs programme and an overview of data collection, processing, scoring and linking, refer to A Guide to PROMs Methodology, which is available at

Data Quality

Important information about the quality of the data from which these statistics are derived is set out in the accompanying Data Quality Statement and the Data Quality Tables, available at

Hospital Episode Statistics

For more information about Hospital Episode Statistics, and to access the many published analyses and datasets, please visit the HES homepage at


Any and all copyrights in the EQ 5D™ questions, their order, layout and images vest in the EuroQol Group ( The EuroQol Group reserves all rights. © 1992 EuroQol Group. EQ 5D™ is a trademark of the EuroQol Group.

Any and all copyrights in the Oxford Hip Score and Oxford Knee Score questions, their order and layout vest in Oxford University Innovation Limited ( and, previously Isis Innovation Limited. Oxford University Innovation Limited reserves all rights. 

Except where expressly stated to the contrary, the Department of Health PROMs questionnaires are protected by Crown copyright. © Crown Copyright 2008–2011.

Last edited: 10 February 2020 1:44 pm