Executive summary (across all report areas)

Executive summary

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

The National Joint Registry started collecting data in April 2003. The ‘cut off’ period for outcomes analysis for this report was December 2015, which gives a potential follow-up of 12.75 years for hip and knee replacements. Data on ankle replacement commenced in 2010 and shoulders in 2012 giving potential follow up of 5.75 and 3.75 years respectively.

The registry now contains over 2 million procedure level records and during the financial year 2015/16 nearly 225,000 were added – which demonstrates the size and growth of this very large dataset.

Registries attempt to collect all possible records of procedures but clearly this is not achievable when dealing with such a high volume of activity. Compliance (the number of cases submitted compared to the number carried out) has grown over the lifetime of the registry, so missing data is more common in the first five years compared to the last eight years. We have monitored compliance by comparing submissions to routinely collected NHS data (Hospital Episode Statistics) but as this does not include privately funded work carried out in the independent sector we have monitored compliance by comparing submissions to the number of implants sold (up to 2 years ago). Both these methods are inexact and we have carried out a detailed national audit of data quality and compliance by comparing NJR submissions with locally collected hospital data for the year 2014/15 to explore this further. This audit is not yet complete and will be reported at a later date but preliminary analysis suggests that over 95% of primary operations and over 90% of revision operations have been captured.

Data quality is extremely important in terms of having confidence in the various outputs of the registry. Statistical methods that allow meaningful comparisons (risk adjustments) are also very important but complex tools. Nevertheless, the NJR is an extremely large dataset and despite missing data the conclusions based on a large sample of activity are likely to be valid. Problems are more likely to be encountered when dealing with low volume activity. Further work and research are ongoing in these areas and will be reported as they mature.

It is important to reflect on the core objectives of the NJR which our Chairman reminded us of in her foreword, namely: to provide early warnings of issues related to patient safety. In this regard I would like to acknowledge the important work carried out by the Implant and Surgeon Outlier Committees, chaired previously by Mr Keith Tucker and Professor Paul Gregg respectively and recently by Mr Peter Howard. As a result of this work several orthopaedic implants have been identified as having potentially worse than expected performance when compared to similar devices. These anomalies have been investigated in considerable detail and shared with industry and the regulator, the Medicines & Healthcare Products Regulatory Agency. I would like to assure the public that the NJR has been instrumental in providing this high level of quality assurance which otherwise would not have been possible.

The format of the report has not changed from last year. Part One (annual progress) is a summary of the in year activities of the NJR and its sub-committees. Part 2 (clinical activity) relates to NJR descriptive data. Both these sections can be found online at www.njrreports.org.uk. Please note that information in Part 2 is available from 2005 in most cases and that the reports are interactive and filterable. So please visit the website and explore this information. Part 3 is the main body of the published report and relates to outcomes after joint replacement. This work has been produced by the highly experienced team at the University of Bristol under the leadership of Professor Ashley Blom and is now also supported by researchers from the University of Oxford. I would like to thank all the team for their excellent work and success in obtaining several high profile peer reviewed publications.

What are the main headlines for 2015?

Many of the trends reported last year continue. The revision estimates following primary total hip replacement are low (less than 5% for the majority of procedures at twelve years) and for some specific brand, bearing combinations can be extremely low (less than 2% at twelve years). These results are extremely impressive and underpin the enormous success and reliability of this operation. These sorts of results should drive confidence to the public and commissioners of healthcare that hip and knee replacement procedures are one of the most effective and cost effective interventions that the NHS has to offer.

As the dataset is so large it is possible for the most frequently used brands or types of replacement to be reported including details of fixation, bearing attributes. Patients and surgeons can therefore see what specific type of hip construct produce low revision rates. This is more relevant than just reporting on how the replacement is fixed to the bone. The good news is that many different types of replacement can produce good results at twelve years. There is not one specific implant that is out on its own at twelve years. The metal-on-metal bearing have generally produced inferior results and are now very rarely used.

It is important to note that the patient has an important effect on how long a hip replacement will last. Revision estimates are much higher in younger patients under-55 compared to patients over-75 years of age. This presumably relates to patient activity. Younger patients should not be denied life changing surgery but they need to be advised that revision may be two or three times more likely at ten years compared to less active patients.

The outcomes of the revised hip are also reported this year. The ten year further revision risk is nearly 15% which is three times greater than the risk for the primary procedure. The message is that revision risk for most patients is low at ten years but if they do fail then the likelihood of further revision is substantially increased. The findings in the report reinforce the principles of the Department of Health’s ‘Getting It Right First Time’ initiative in England.

The knee replacement data in many ways mirrors that of hip replacement. As reported previously partial or unicompartmental knee replacement have almost three times the revision risk of a full total replacement. This is where one needs to be cautious in interpreting registry data. Partial knee replacement is a less invasive operation with lower associated mortality and morbidity and therefore may confer advantages in other areas apart from the outcome measure of revision. It is important that surgeons discuss these differences with patients and set out the issues in question. The number of operations carried out by surgeons may be important in driving lower revision rates and there are professional initiatives to discourage surgeons from carrying out low volumes of partial replacement.

Data is presented on ankle and shoulder replacements and I would like to thank members of the British Elbow and Shoulder Society (BESS) and the British Orthopaedic Foot and Ankle Society (BOFAS) for assisting in analysing and understanding these relatively early but complex outputs.

What is also of particular interest for this year is our initial analysis of Patient Reported Outcome Measures (PROMs) in relation to shoulder replacement. The PROMs data highlights the substantial benefit and significant improvement of the elective patients sampled. These data are encouraging, especially given the large cohort being analysed.

Concluding acknowledgements

The Medical Advisory Committee (MAC) has been an extremely important forum for professional engagement and I would like to thank Mr Tim Wilton, president of the British Orthopaedic Association (BOA), and the specialist surgical societies, British Hip Society (BHS), British Association for Surgery of the Knee (BASK), BESS and BOFAS. Additionally, I would like to acknowledge and thank Professor Mark Wilkinson, Chair of the Research Sub-committee for establishing and developing the NJR research agenda, governance and data access platform, Mr Matthew Porteous, Chair of the Regional Clinical Coordinators Sub-committee, Elaine Young, NJR Director of Operations, and our Chairman, Laurel Powers-Freeling. The NJR continues to work with many stakeholders including patients, regulators, hospitals, industry, individual surgeons and procurement, to ensure accurate annual reporting. I would like to conclude by acknowledging the support and expertise of Northgate Public Services for providing the IT support to the NJR to achieve this.

Finally, I would like to thank all members of the NJR Steering Committee, sub-committees and indeed all the orthopaedic surgeons in hospitals that contribute data. The collective effort ensures that the National Joint Registry positions itself as the world-leading arthroplasty registry, driving patient safety across the whole orthopaedic sector.