Data Completeness and Quality

The linkability rate for 2023/24 was 93.91%, a decrease from the adjusted figure for 2022/23 (97.16%). The overall linkability for all records submitted to the registry since 2003 is 94.27%. 

The linkability rate compares the number of records with the patient’s national identifier (NHS number in England and Wales, and HCN in Northern Ireland) with the number of procedures recorded in the registry. National identifiers are validated or traced (if not originally submitted) via the national tracing services using the patient’s name, date of birth and postcode. For England, Wales and the Isle of Man, the tracing is undertaken using NHS England’s Data Access Tracing Service (DATS), whilst tracing of HCN numbers in Northern Ireland is carried out by Health and Social Care Northern Ireland.

A unique national identifier is required to link all primary and revision procedures relating to the same joint for a single patient. This linkage is essential to calculating clinical outcomes and without high rates of national identifier submission and tracing, our ability to monitor clinical and implant performance is adversely affected. Figure 1.3 below shows the linkability rate since 2003.

Successful tracing of national identifiers is also dependent on the correct submission of a patient’s name, date of birth and postcode. 

The informed consent rate for 2023/24 was 93.45%, a slight decrease from informed consent in 2022/23 (94.66%).

The informed consent rate compares the number of records submitted where the patient has either agreed or refused to have their personal data stored in the registry, with the total number of procedures recorded in the registry. If consent is refused, then the details of the operation and implants are recorded but no patient details are collected. Patients have to give voluntary, informed consent to have their personal data held in the registry alongside their operation data. This personal information is essential to link patients’ primary and revision procedures together in order to monitor the longer-term outcomes of joint replacement surgery and the performance of implants used. Therefore, without high rates of consent, we cannot achieve our strategic objectives.

Support under Section 251 of the NHS Act 2006 for English and Welsh hospitals

In England and Wales only, we record consent in one of three ways: ‘Yes’, ‘No’, or ‘Not Recorded’. The support granted under Section 251 enables the NJR to collect patient details where ‘Not Recorded’ is indicated for consent. This is justified for reasons of patient safety as it enables us to identify those patients who may have had a prosthesis implanted that is subsequently subject to either an MHRA Medical Device Alert or an MHRA Field Notice. Any patient declining consent will not be identified in the event of either a Device Alert or Field Notice being issued that related to a device that they had had implanted, or be contacted and invited to take part in any follow-up audits (e.g. PROMs) or research projects that use NJR data. 

Patients rarely decline consent and many hospitals achieve consent rates of 100%. Lower consent rates are generally caused by a lack of robust processes which sometimes mean that the completed consent form is not available to the person submitting the procedure details to the registry. The consent rate for trauma surgery is also lower than that for elective surgery. This is due to patients being admitted as an emergency, and usually unable to make informed consent, and not going through the ‘normal’ elective admission process with staff familiar with the NJR process and the need to capture consent.

The latest available compliance rate (1 April 2022 to 31 March 2023) from the NJR Data Quality Audit for all submissions was 97.66% for all participating hospitals.

Our automated Data Quality Audit process enables the comparison of local hospital records (for both NHS and independent sector hospitals) directly with the procedures submitted to the registry. This comparison identifies those procedures that have not been submitted to the registry or may have had incorrect information submitted, and which can then be entered or corrected retrospectively. The automation means that the audit can be undertaken at a time when hospitals can manage it and many now complete the audit quarterly rather than waiting a year. Records that are found on the local hospital system or HES/PEDW but not on the registry can be subsequently uploaded bringing compliance as near to 100% as possible.

The initiative has greatly reduced the number of mismatches between registry and hospital data; compliance and data accuracy has improved greatly since the process was fully embedded in all hospitals. You can learn more about the NJR’s data quality strategy here.

Information about the key indicators of data completeness and quality

It is mandatory for the providers of joint replacement surgery listed below to collect and submit data to the registry

• All NHS trusts and foundation trusts within the jurisdiction of NHS England
• All hospitals within the jurisdiction of NHS Wales 
• All hospitals in Northern Ireland performing procedures funded by Health and Social Care Northern Ireland (HSCNI) 
• All independent sector hospitals in England and Wales

Performance against the three key indicators of data quality (compliance, consent, and linkability) varies slightly throughout the year. Performance against the three indicators was lower in 2020/21 than other years due to the COVID-19 pandemic. Current hospital-level performance against these key indicators is available in the Downloads area.

The number of procedures submitted, with the corresponding consent rates, for each hospital are provided through the NJR StatsOnline service. Performance against all indicators is also included in the Annual Clinical Report provided to trust and health board senior management and to independent healthcare companies. Surgeons are also able to access Annual Clinical Reports for those hospitals in which they practice.