UK SAFE Project

UK SAFE: Towards UK poSt Arthroplasty Follow-up rEcommendations

There is increasing pressure to identify cost-saving measures across the NHS. Recent work suggests many centres are curtailing primary hip and knee arthroplasty follow-up services to deal with the growing pressure on their services. However, such disinvestment is without evidence-base and raises questions of the consequences to patients. This project will examine the requirements for arthroplasty follow-up and produce evidence and consensus-based recommendations as to how, when and on whom follow-up should be conducted. Work packages one to three will be discrete research projects that will be conducted independently. Knowledge and information from each project will feed into and inform the other work streams with some tasks being conducted in parallel.

Work package one: Systematic Literature Review

Literature searches will be designed in line with guidance for qualitative evidence synthesis, systematic reviews, cost-effectiveness reviews and rapid reviews. They will identify published and unpublished papers, dissertations, conference abstracts and ongoing research in follow-up care pathways for primary knee arthroplasty.

Work package 2a: (RO-HES)

This work package (RO-HES) is a retrospective cohort study using routinely collected (observational) NHS data from:

  • NHS Digital: Data will be obtained from the Hospital Episode Statistics (HES) dataset in relation to Accident and Emergency, Inpatient and Outpatient episodes in hospitals in England.
  • Research One: Data will be obtained from this research database in relation to General Practice for patients identified by NHS Digital.

Data from these sources will be linked to construct longitudinal records for analysis.

The University of Leeds is the sole data controller for this work package.

Work package 2a: (University of Oxford)

National linked datasets:  CPRD-HES, and NJR-HES-PROMS

  • Hospital Episode Statistics (HES) database holds information on all patients admitted to NHS hospitals in England
  • Clinical Practice Research Datalink (CPRD) comprises the entire computerised medical records of a sample of patients attending general practitioners (GPs) in the UK
  • Patient-Reported Outcome Measure (PROM) data has been collected on hip and knee replacements performed in public hospitals in England.

National Joint Registry (NJR) for England, Wales and Northern Ireland collects information on all hip and knee replacements performed each year in both public and private hospitals in England, Wales and NI since 2012

These routine data from national datasets will be analysed to determine when revision happens to inform when follow-up should occur and identify patients most likely to require revision to target who should be followed-up.

Large datasets from the NJR alongside data from NHS Digital will be used during this study. The personal identifiers of patients who had knee replacement surgery and consented for their details to be stored in the NJR will be securely transferred to NHS Digital.  NHS Digital will link the data to information it collects and extract details of all hospital admissions (HES) for the study cohort and Patient Recorded Outcome Measures (PROMS).

NHS Digital will securely transfer the linked data to the University of Oxford as pseudo-anonymised data (All identifiers will be removed and replaced with a unique patient ID).  The NJR will securely transfer pseudo-anonymised information from its records to the University of Oxford using the same unique ID so that the data can be linked by the University of Oxford and processing in such a way that researchers will not be able to identify patients.

Access patient information and the NJR study website

The links below have more information on the National Joint Registry and NHS Digital and how patient information used. You can find out more about how data is collected and how patients can opt out.

National Joint Registry Patient consent

NHS Digital – Data collection

NHS Digital – Opt out

University of Oxford is the sole data controller for this work package.

Work package 2b: Prospective study

After a hip or knee replacement, some patients are offered a periodic check-up (referred to as ‘follow up’) and others are not. It is not known if this will make any difference to the outcome of knee or hip replacement surgery. This research will investigate if individual patient-centred follow-up can better identify potential problems to the benefit of all concerned.

Work package three: Health Economic Analysis and Markov model

This work package aims to determine how follow-up should occur by:

  • Building inferred models of care from the data obtained in work package one and work package two
  • Determining the hazard ratios for revision over time and according to patient characteristics
  • Estimating the primary and secondary care costs of current practice and the different models of follow up
  • Using Markov modelling to simulate long-term costs and Quality Adjusted Life Years (QALYs) associated with each selected care model against current practice
  • Estimating the proportion of ‘timely’ revision (for instance before a joint fails catastrophically and so simpler revision surgery is possible) associated with each model of care
  • Identifying where disinvestment could safely happen without risk to individuals
  • The methods to be followed in order to achieve each of the specific aims of this work package vary depending on the nature of the question and the being data used.

Work package four: Consensus – Delphi Consensus Study

Evidence from work packages one to three will feed into a consensus panel, using the NICE Guideline development model. This will involve 25-30 participants including patients, surgeons, GPs, and commissioners. The output will be a policy document which includes a stratification algorithm for appropriate follow-up for an individual patient.


Protocol paper:

Funding acknowledgement: The project UK SAFE project was funded by the NIHR Health Services and Delivery Research Programme (project reference: 14/70/146)

Department of Health disclaimer: The views expressed are those of the author(s) and not necessarily those of the NHS, the NIHR or the Department of Health.

For more information on the UK SAFE Project, please contact:

Dr Sarah Kingsbury


Tel: +44 (0)113 392 4878