A critical examination of the Australian Orthopaedic Association National Joint Replacement Registry: Improving outcomes of hip and knee replacement

Abstract

Introduction Total Hip Replacement (THR) and Total Knee Replacement (TKR) are effective operations for patients with end stage arthritis who can no longer be adequately treated non-operatively. It is increasingly important that these procedures be closely monitored so that the best results can be achieved for patients and optimum use of health resources achieved. Joint replacement registries collect, analyse and report data on patients undergoing joint replacement surgery and can monitor numbers and changes over time, evaluate outcomes and identify patient and prostheses factors associated with these outcomes. The aim of this thesis is to study the impact of the Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) on hip and knee replacement in Australia. It will explore whether joint replacement outcomes have improved since the introduction of the Registry and critically assess the role of the Registry in this process. Within this main aim, the thesis addresses 4 specific research questions: 1. How are prostheses that are not performing as well as others in their class identified and what are the consequences of this? 2. How does the AOANJRR monitor the impact of new technology such as computer navigation for TKR and the consequences of this? 3. How does the AOANJRR monitor the introduction and impact of new materials with specific reference to crosslinked polyethylene for both THR and TKR? 4. What role has the AOANJRR played in the change of practice, policies and outcomes of hip and knee Replacement in Australia? Methodology The thesis involves a systematic investigation using data from the AOANJRR to address the research questions. The questions were appropriately defined to retrieve information from the Registry for critical examination and analysis. The basic framework is empirical. The processes and analytical methods used to answer specific quantitative research questions are standard and currently in place at the Registry. The research questions were developed to examine data that could specifically be addressed by the AOANJRR and with minimal information available from other national registries or other sources. These were designed with the aim of determining whether any demonstrated improvements in joint replacement outcomes were likely due to the Registry. Results The revision rates for hip and knee joint replacements have improved since the inception of the Registry. The revision burden for total joint replacement is defined as the proportion of all hip and knee replacement procedures that are revisions. In Australia, the revision burden for total hip replacement has declined from 13.1% in 2002/2003 (the first year of full Registry national data) to 9.8% in 2015/2016. For knee replacements the revision burden has declined from 9.3% in 2002/2003 to 7.4% in 2015/2016. This equates to a 25% reduction in the burden of revision for hip replacement and a 20% reduction for knee replacement over the respective periods. The rate of revision for primary THR has declined from 4.8% at 6 years for the time period 2003-2006 to 3.6% at 6 years for THR performed between 2011 -2014. A similar reduction is also seen for TKR over the same period with a decrease in the rate of revision from 5.1% for procedures performed from 2003 -2006 compared to 3.8% for procedures performed from 2011-2014. The role of the Registry in improving the outcomes of joint replacement is addressed within the context of the research questions. The first paper described the process and the evolution over time of methods the Registry has developed to identify devices with a higher than anticipated rate of revision. As a consequence of reporting these devices, there has been a 67% reduction in THRs and a 76% reduction in the use of TKRs that have been so identified in the following year. The international consequence of this process is followed up later in the thesis. TKR has a higher rate of revision for younger patients and methods to reduce this rate of revision are important. The use of computer navigation results in an overall reduction in the rate of revision for patients < 65 years of age and a reduction for loosening in patients of all ages. 4 The introduction of crosslinked polyethylene (XLPE) results in a prosthesis specific reduction in revisions for both TKR and THR compared to the use of the standard conventional non cross-linked polyethylene. For younger patients, <55 years of age, there is a fivefold reduction in the rate of revision for THR at 15 years compared to the use of conventional non cross-linked polyethylene. The Registry was the first to report a reduction in revision with the use of XLPE for hip and knee replacements. This has important implications and may enable younger patients to undergo surgery, confident of a reduced need for revision in the long term. The penultimate chapter outlines the contribution that the Registry has made to the improved outcomes of joint replacement in Australia by examining the interaction with multiple stakeholders. The chapter illustrates the many ways this has been achieved and uses case examples of feedback with resultant change of practice. The interaction of the Registry with the Australian Government, Regulatory authorities, Industry, and Medical Insurers outlines the importance of involving all stakeholders when striving to improve healthcare outcomes. Conclusion There has been a substantial improvement in the outcomes of hip and knee replacement in Australia over the past 14 years. This thesis outlines the ways by which this has been achieved and outlines the critical role of the Registry in achieving these improved outcomes.