Executive summary (across all report areas)

Executive summary

Mr Martyn Porter, NJR Medical Director and Chairman, Editorial Board 

The National Joint Registry’s maturing dataset, now in its 14th year of reporting, offers the orthopaedic community the invaluable ability to see important determinants that influence the outcome and longevity of joint replacement procedures. Monitoring and reporting high quality, robust data suitable for decision-making remains the registry’s core mission and I’m delighted to present this year’s findings.

To ensure accurate annual reporting the NJR continues to work with many stakeholders including hospitals, industry, and individual surgeons. As outlined by the NJR Chairman in her foreword, the NJR’s remit has naturally broadened and the ability for the dataset to drive forward change in other areas has grown – from patient recorded outcome measures (PROMs) to implant price benchmarking, from research to surgeon accreditation.  As well as also being an important source of evidence for regulators, such as the Care Quality Commission (CQC), to inform their judgements about services.

The NJR’s Annual Report is a fundamental pillar in all of this and showcases how we monitor the performance of implants, hospitals and surgical technique but also how the registry is driving quality improvement in the orthopaedic sector as a whole.

Main headlines for 2016: procedures and data quality

For 2016, there were a total of 242,629 cases submitted to the NJR, an increase of over 20,000 on the previous year, which brings the total number of records in the registry to approximately 2.35 million. This is despite concern that the overall number of joint replacement procedures being undertaken was decreasing. The constantly high number of cases submitted per year suggests continuing high levels of patient confidence and clinical performance, in what is a remarkably successful surgical intervention.

The increase in cases submitted during 2016 could also be in part due to the NJR’s sustained programme to improve data quality and compliance in the registry. Namely, this has been the work surrounding the data quality audits rolled-out across all eligible NHS hospitals, and for the first time during 2016, independent sector hospitals too. As such, the NJR has been able to work with hospitals to improve their NJR processes, to ensure that all eligible primary and revision joint replacement operations are recorded on the database and put forward for analysis.  
Many hospitals work hard to ensure that they record all eligible procedures. However, the completeness of data within the NJR is reliant on the input at the local level, which the audit has highlighted is subject to variation across hospitals.  

We are now able to fully report the audit’s findings in year one. These findings can be found on pages 18-20. I was able to offer some very early analysis in last year’s Annual Report for year one of the audit, which highlighted a really pleasing low overall level of missing records. These trends continued as more hospitals completed the audit. However, the audit found that the proportion of missing data is greater for revision procedures. The failure of hospitals to upload revision procedures into the NJR is concerning, as linked revision procedures form the basis of the analyses of implant failure and surgical performance – which fundamentally underpin the core purpose of the NJR. 

Put another way, one of the NJR’s principal outcomes of interest is revision surgery, an indication of implant failure or surgical performance. This is determined by linking a primary arthroplasty procedure to a secondary procedure, which typically occurs a number of years after the primary procedure. Analyses of revision estimates in this year’s Annual Report highlight why compliance with reporting revision surgical procedures is essential to estimate implant failure rates and surgical performance more accurately. Further investigation is underway to ascertain whether these are random events or a systematic under-reporting of revision procedures.

Main headlines for 2016: outcomes

Across all joint procedures recorded in the registry, revision estimates following primary joint replacement procedures remain low. For example, primary total hip replacement revision estimates are less than five percent for the majority of procedures at thirteen years. Knee replacement data in numerous ways mirrors that of hip replacement. Similarly, there are very positive outcomes reflected in the ankle, shoulder and, now for the first time, elbow joint replacement data too.

These outcomes are extremely impressive and underpin the enormous success and reliability of joint replacement surgery. These sorts of results should help drive greater confidence in the public and with commissioners of healthcare, that joint replacement is one of the most effective and cost effective interventions that the NHS has to offer.

Furthermore, data for this year outlines that osteoarthritis is the main diagnosis for primary hip replacement and almost exclusively the diagnosis for primary knee replacement, in 90% and 99% of cases respectively. Therefore, we should not lose sight of the fact that joint replacement surgery offers significant benefits – getting patients back to their chosen lifestyle sooner, free from pain with improved mobility. 

However, those in the orthopaedic community must continue to note an important trend emerging from the data, which highlights that the patient has an important effect on how long an implant will last. This year’s analyses continue to show the increased risk of revision associated with younger patients across all joint procedures recorded in the registry. This is particularly important given the increase in total numbers of younger patients undergoing joint replacement.

As previously outlined by the NJR, if younger patients are most likely to need at least one revision surgery in their lifetime, then we must use the maturing dataset of the NJR to get the first-time surgery as right for the patient as possible.

For example, the revision rate for total hip replacement increases at a faster rate over time for younger patients. To explore this further, this year’s report examines the effect of age and gender on hip revision rates across the construct groups for the first time. This will assist clinicians and patients in choosing classes of prostheses that are effective for their particular age and gender, and makes for interesting reading.

Elsewhere with hip replacement data, our analysis confirms that choice of head size is an important factor in determining revision outcome. For both metal-on-polyethylene and ceramic-on-polyethylene bearing choices, higher failure rates appear to be associated with larger head sizes. Importantly, this is particularly the case with 36mm heads used with cemented fixation and head sizes of 36mm and above with hybrid and uncemented fixation.

Linked to the theme of younger patients, the knee replacement data again continues to show similar trends. Given partial knee replacement surgery is used generally in younger patients, the importance of the effects of patient factors which influence the outcome must be considered. For patients undergoing total knee replacement at the median age of 69 years of age, the 13-year risk of revision is just over 4%. However, for total knee replacement patients under the age of 60, the risk increases with decreasing age, reaching 10% for those under 55 years old. This pattern is magnified in unicondylar replacement, with patients under the age of 55 facing a 25% chance of revision by 13 years. This has been a consistent finding across all annual reports.

Further improvements to the representation of shoulder replacement data have been made. We have made the distinction for the first time between stemmed and stemless humeral implants, as well as improved representation of data in stem branding to reflect which implants are being used less or more frequently year on year. Naturally, trauma and elective procedures continue to be separated out.

Elsewhere, we also report on ankle and elbow replacements (Sections 3.7 and 3.9). As these are carried out less frequently and we have a shorter follow up period (since 2010 and 2012 respectively), data are still at a relatively early stage. However, I am pleased that the British Elbow and Shoulder Society (BESS) and the British Orthopaedic Foot and Ankle Society (BOFAS) continue to work very closely with the NJR to take the collection and analysis of the data forward.  

Concluding acknowledgements

As well as the pages of this report, I would encourage you to explore the NJR’s dedicated annual report website at www.njrreports.org.uk . The website offers a helpful interactive platform for Part 2 of the report, which is the descriptive NJR data; supporting appendices; and, when published, the latest NJR Patient and Public Guides to the annual report.
The NJR continues to work with many stakeholders including patients, regulators, hospitals, industry, individual surgeons and procurement, to ensure accurate annual reporting. To conclude, I would like to thank our Chairman, Laurel Powers-Freeling, and all members of the NJR Steering Committee, which is ably supported by the NJR Management Team, led by NJR Director of Operations, Elaine Young. My thanks to the NJR Editorial Board and other sub-committees who supported the production of this report, and indeed all the orthopaedic surgeons in hospitals that contribute data. The collective effort ensures that the National Joint Registry maintains its position as the largest and world-leading arthroplasty registry, with a sharp focus on patient safety.

I would like end by acknowledging the hard work undertaken and led by teams at the University of Bristol with support from colleagues at the University of Oxford, who have once again provided excellent provision in terms of analysing the outcomes following primary surgery and the many peer reviewed publications which have been produced from the registry data. I would particularly encourage you to explore the research published since the last annual report on ethnicity and joint replacement  and the main cause of death following primary total hip and knee replacement for osteoarthritis . Finally, to also acknowledge Northgate Public Services Ltd who provide the IT support and expertise for the NJR to achieve these outputs.