How does the National Joint Registry's work benefit me? How can I become a part of the NJR's Regional Support network? Who are the working groups the NJR works with? We aim to answer all your questions whether it be in person at a conference, in our Annual Report and weekly reports or here on out website

Making clinical audit data transparent:

About the NJR Annual Report statistics at

In 2011, the government’s transparency and open data commitments outlined that clinical audit data within the National Clinical Audit and Patient Outcomes Programme (NCAPOP) would be made available at The National Joint Registry is not part of NCAPOP, but is hosted by the Healthcare Quality Improvement Partnership and participation is mandated for NHS Trusts in England via the NHS Standard Contract.
What information is being made available?

The transparency initiative described here specifically applies to England. However, importantly the NJR will publish the same level of information for all territories where achievable. The results of the data analysis, including hospitals in Wales, Northern Ireland, the Isle of Man and Guernsey, are published each year as part of the NJR Annual Report.

The data published on this page only applies to England. It does not include any data about individual patients nor does it contain any identifiable data. It also only available in a CSV format. You may prefer to look at the same data in the Annual Report available at

Using and interpreting the data

The data covers the period January to December in the year prior noted in each file name.

It shows information relating to how individual NHS trusts and hospitals in England have performed against a range of key measures including whether they have been identified as an ‘outlier’ for revision rates, indicated by the ‘yes’ or ‘no.’

Key points to note:

  • The information is sent directly to hospitals who should use the results to look at those areas where improvement or investigation may be needed
  • The information requires careful interpretation and it should not be looked at in isolation when assessing standards of care. Your hospital will be able to explain their results and what actions they may be taking to improve them
  • Information is routinely shared with the Care Quality Commission who use this information, along with other sources, to assess hospital performance against standards of national care

What does the data cover?

Key measures

Hospitals have been awarded a green (≥95%), amber (≥80%) or red (>80%) rating to reflect how well they performed based on consent, compliance and linkability.

  • Compliance (Trust-level): Participation in the NJR is mandatory so all operations that take place in a given year should be recorded in the NJR. This will maximise NJR data quality and ensure that the NJR can report on a ‘full’ picture of what is happening at any individual NHS Trust.
  • Consent (hospital-level): The percentage of records submitted to the NJR with patient consent confirmed. This is vital in order to link primary and revision operations together. Measuring the time in between operations, for all patients, tells us how well different implants and surgeons are performing.
  • Linkability (hospital-level): The proportion of records submitted with both patient consent and NHS numbers. Linking operations together on the NJR is done using NHS numbers.

Outlier analysis

Outlier analysis aims to identify ‘unusual differences’ in data from ‘normal variations’ which may indicate the need for further investigation. For mortality and revision rates, an outlier will be a hospital with an unusually high proportion – more than would normally be expected.
The NJR can work out who is an outlier by plotting statistical control methodology results on a Funnel plot. Using this format allows hospitals of different sizes to be compared and adjustments are also made for patient characteristics that affect revision rates for example, age group and gender.

The NJR has also listed the following information for each hospital:

  • Number of consultants
  • Average ASA grade – this is the grade of patient health prior to surgery excluding the joint problem being addressed
  • Percentage of male patients
  • Average age at operation
  • Percentage of 10A rated acetabular hip and femoral hip

Accessing the data

Data from the NJR for England will be available in a CSV file each September. The same data is available on the website.

Which level of data is being reported?

Compliance information is published at trust-level. All other information is published by individual hospital in the NHS and private sector.

What period does the data cover?

The data covers the period January to December in the year of each CSV file name.

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