Data Completeness and Quality

There are currently three types of organisation submitting details of hip, knee, ankle, shoulder, and elbow joint replacement surgery to the registry.

• NHS hospitals
• Independent sector hospitals
• Independent Sector Treatment Centres (ISTC)

There are no ISTCs in Wales, Northern Ireland, the Isle of Man or Guernsey.

Table 1.3 below shows the number of reported procedures by type of provider from 1 April 2015 to 31 March 2021.

The proportion of procedures undertaken in NHS and independent hospitals has been affected by the COVID-19 pandemic, as NHS hospitals suspended many of their elective operations. The pie charts in Figure 1.3, below, compare the proportion of procedures undertaken between April 2019 and March 2020 in NHS hospitals, independent sector hospitals, and independent sector treatment centres, with the same period the following year. The procedures in the independent sector are further subdivided into those procedures which were either NHS-funded or privately funded.

Whilst the proportion of NHS-funded procedures undertaken in the independent sector increased slightly, the proportion of independently funded procedures almost doubled. The actual number of procedures undertaken in independent hospitals exceeded the number of those carried out in NHS hospitals.

As at 31 March 2021, 3,182,133 hip, knee, ankle, shoulder, and elbow joint procedures had been submitted to the registry: the NJR continues to be the largest orthopaedic registry in the world.

There were 131,603 procedure submissions in 2020/21, a drop of 47.7% on the total reported last year. This is a direct result of many units ceasing elective surgery during the COVID-19 pandemic.

Operation totals

Table 1.1 below shows, the number of procedures reported, by country and joint type, from 1 April 2015 to 31 March 2021. Due to small numbers, data for the Isle of Man and Guernsey are included with the figures for England.

Operation types

Table 1.2 shows the number of procedures reported, by type, from 1 April 2015 to 31 March 2021. Primary procedures make up 91.5% of all procedures reported during 2020/21. The number of ankle, elbow, and shoulder revisions as a proportion of both primaries and revisions is higher than that for hips and knees.

The linkability rate for 2020/21 was 93.99%, a decrease from the adjusted figure for 2019/20 (97.15%). The overall linkability for all records submitted to the registry since 2003 is 93.3%.

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 Isle of Man, the tracing is undertaken using NHS Digital’s Data Access Tracing Service (DATS), whilst tracing of HCN numbers in Northern Ireland is carried out by the Health and Social Care of 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: without high rates of national identifier submission and tracing, our ability to monitor clinical and implant performance is adversely affected. Figure 1.2 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 2020/21 was 89.9%, a decrease from informed consent in 2019/20 (94.9%). This is the lowest rate since the year 2007/2008.

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 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 are required to give voluntary, informed consent to have their personal data held in the registry alongside their operation data. This personal information is essential in order to link patients’ primary and revision procedures together 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 all of our performance monitoring goals.

Patients rarely decline consent and many units achieve consent rates of 100%. Lower consent rates are generally caused by a lack of robust processes which, for example, mean that the completed consent form is not available to the person submitting the procedure details to the registry. Figure 1.1 below shows the informed consent rate since the beginning of the registry.

An examination of the reason for the drop in the consent rate in the latest reporting period shows that it is due to the significant drop in the number of elective procedures, as a result of the COVID-19 pandemic, with a resultant increase, as a proportion, of the number of non-elective procedures.  Historically, the consent rate for non-elective surgery has always been lower than that for elective surgery. This is due to patients being admitted as an emergency, unable to make informed consent, and not going through the ‘normal’ elective admission process with staff familiar with the NJR process of requirements to capture consent. We expect that with an increase in the number of elective procedures being undertaken, the consent rate will rise to previously higher levels.

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

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. The ‘Not recorded’ rate for 2020/21 was approximately 9.66% (an increase of over 4% on 2019/20) which means that approximately 12,7000 patients did not have their consent recorded and who, without Section 251 support, could 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. As a consequence, this group of patients cannot be contacted and invited to take part in any follow-up audits (e.g. PROMs) or research projects.

The compliance rate from 1 April 2019 to 31 March 2020 for all submissions was 95.88% for NHS hospitals in England and Wales. The data for the year 1 April 2020 to 31 March 2021 is not yet available.

Due to the COVID-19 pandemic, hospitals were directed at the end of March 2020 to cease inputting records to audits and to divert staff to higher priority tasks, therefore a number of elective procedures were not initially reported as data entry activity wasn’t then resumed until July that year. It is expected that these procedures will be identified by units and entered retrospectively or submitted as part of our ongoing data quality audit programme

Prior to 1 April 2014, we measured the compliance rate by comparing the number of levies raised for implant sales against the number of procedures submitted to the registry. With the adoption of a hospital subscription model in April 2014, it is no longer possible to measure the compliance rate in this way. We cannot, therefore, provide a chart showing annual compliance rates over the life of the registry.

Compliance for hip, knee, ankle, elbow and shoulder procedures is compared to submissions made to the Hospital Episodes Statistics (HES) service in England and to the Patient Episode Database Wales (PEDW) service in Wales. This comparison is based on a defined set of OPCS4 codes which can be obtained by contacting us if required.

Whilst the use of HES and PEDW data enables the measurement of the rate of compliance for trusts and health boards, it does not include those procedures undertaken in the independent sector. We have signed a data sharing agreement with the Private Healthcare Information Network (PHIN) that will, in the future, provide data that will enable us to calculate compliance rates for independent sector hospitals.

Our automated Data Quality Audit process enables the comparison of local hospital records directly with the procedures submitted to the registry. This comparison identifies those procedures that have not been submitted to the registry and which can then be entered retrospectively. The service is still being rolled out but it has significantly reduced the time and effort required to audit NJR submissions and increasing numbers of hospitals are achieving the high standards demanded to qualify for recognition through our annual awards process.

About the key indicators of data completeness and quality

It is mandatory for the following providers of joint replacement surgery 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 the previous year. The drop is due to the COVID-19 pandemic. Unit-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 chief executives and to independent healthcare companies. Surgeons are also able to access Annual Clinical Reports for those hospitals in which they practice.