NJR researcher

NJR Annual Research Programme

We work closely with the University of Bristol to develop an internal annual research programme, deciding on four areas of focus. These proposals are then managed through the NJR Research Committee as internally-supported project proposals.

The studies often reflect significant areas of interest for the whole orthopaedic community and current and ongoing areas of work include:

  • Inequalities in provision and outcomes of arthroplasty performed in England.
  • Development of an Orthopaedic Arthroplasty Specific Morbidity Index.
  • Revision Total Hip Replacement (THR) and Total Knee Replacement (TKR).
  • Comparing the performance of hip and knee implants on patient-reported outcomes.

The annual research programme is detailed in the NJR Annual Report.

Inequalities in provision and outcomes of arthroplasty performed in England

We aim to describe inequalities between patient groups and geographical variation across Clinical Commissioning Group (CCG) areas and their temporal trends with regards to access to arthroplasty (provision), type of arthroplasty received and outcomes. We will focus on hip and knee but extend to other joints where numbers allow. This would provide the evidence-based framework to identify recent inequalities (requiring specific monitoring) and longstanding inequalities (requiring prioritisation) to guarantee fairness in access to, quality and outcomes, of health care for patient receiving arthroplasty across the NHS.

Development of an Orthopaedic Arthroplasty Specific Morbidity Index

The aim of this study is to investigate whether early mortality, revision, and morbidity (as measured by PROMs) can be predicted after total joint replacement by the use of easily accessible data that are routinely collected in daily clinical practice or whether an orthopaedic arthroplasty specific morbidity index is required.

Revision Total Hip Replacement (THR) and Total Knee Replacement (TKR)

This body of work aims to explore the factors associated with revision and its outcomes. Our aim is to describe what a patient can expect from a revision in terms of prosthesis survival time and the likelihood of operational success. We will also predict the future burden of revision surgery.

Comparing the performance of hip and knee implants on patient reported outcomes.

Patient reported measures of hip and knee pain and function have been collected nationally since 2009 for all patients receiving a primary hip or knee replacement operation. This information is not currently reported in the National Joint Registry annual reports.

Each year the NJR publishes its annual report which includes the failure rates of all the different brands used in hip and knee replacements.

Revision surgery is not a complete marker of success. A device may be classified as successful if it survives for 15-years, but a patient may disagree should they have experienced persistent pain and disability. Up to 20% of patients report persistent pain following joint replacement surgery. Analysis of revision rates alone fails to identify patients with persistent pain or disability. Therefore, there have been calls for methods to measure pain than can subsequently be used in conjunction with revision rates for accurately monitoring outcomes in hip and knee replacement surgery.


Within this study, our aim is to compare and scrutinise the differing performances between the implant brands of different prostheses for pain and functional outcomes.


By selecting a hip / knee brand with a highest improvement in pain and functional outcome as a reference group, we will perform statistical analyses to directly compare the performance of all the stem and cup combinations used in hip replacements and all the knee brands used in knee replacement surgery against this reference.


This will demonstrate if any brands are performing poorly in comparison to the best performing implants, allowing patients and surgeons to make more informed decisions about the relative performance as judged by patient reported pain and functional outcome of the construct of each brand.

Research Portfolio

Details of all research projects that have been approved by the Research Committee, and any associated publications can be found here:

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