FEMORAL: Factors affEcting MortALity, morbidity and patient outcomes after joint replacement surgery.

In the UK the life expectancy is increasing and the population is ageing. One common disease associated with ageing is osteoarthritis. Osteoarthritis has serious consequences in terms of mobility, quality of life and joint pain. Currently there are no effective methods which prevent the development of osteoarthritis. Therefore most research relates to different treatment strategies. One method of treating osteoarthritis is by joint replacement surgery e.g. hip and knee replacements.

Joint replacement surgery can greatly improve the quality of life by improving mobility and reducing joint pain. However there are a large number of different types of replacement joints and approaches to join replacement surgery. Currently it is unclear which type of replacement joint, or surgical approach provides the greatest improvement to an individual's mobility, quality of life, and reduction in pain. In addition, it is also unclear if all surgeons and surgical units perform equally, and what affect this may have on the success or failure after join replacement surgery.

This project aims to compare the differences in replacement joints and surgical approaches, surgeons and surgical units to identify the best combination which improves mobility and quality of life the most.

This project will use existing data collected on joint replacement surgery by the national joint registry (NJR) of England and Wales. I will use a variety of different methods to investigate the factors that predict successful joint replacement surgery. I investigate the affect of different replacement joints, patient characteristics, pre operative mobility, surgical approaches, surgeons, and surgical units on the success of joint replacement surgery.

The findings of this research will greatly improve our understanding of what replacement joints, and types of surgery give patients the best quality of life, reduction in pain, greatest mobility and independence. I will identify high performing surgeons and surgical units with the best patient outcomes and communicate the results to patients, surgeons, hospitals and politicians.

I hope the findings of this research will allow surgeons to tailor the use of replacement joints and surgical approaches to the individual, and improve patient outcomes including mobility and quality of life for the UK population. I hope the identification of high performing units will allow targeted research to understand why the units excel, and then distribute that information to other hospitals and surgeons. In addition, we hope that surgeons and units with unsatisfactory results can be investigated and corrective measures implemented more quickly. I also hope that I will develop a framework to analyse data from the NHS in many different disciplines so robust analyses can be conducted quickly and easily.

Background: Osteoarthritis in the elderly is very common in the UK and around the world, and can result in a significant reduction in mobility, quality of life and increased economic burden. Joint replacement surgery (JRS) is one method of treating osteoarthritis, but analysing and interpreting data arising from the NHS presents specific challenges.

The organisational structure of the NHS gives rise to a dependent structure of data. The hierarchical structure of organisational data is commonly represented using a traditional multi-level model, but in practice violations of this strict hierarchy occur, as surgeons and patients move between surgical units and surgeons respectively.

Aims: We aim to improve patient outcomes and reduce mortality and morbidity after JRS by identifying factors which affect the efficacy of JRS.

Methods: Using data from the National Joint Registry we aim to explore the aims and objectives of the fellowship by employing multiple membership multi-level modelling techniques. Features of the prosthetic implant and surgeon preference will be incorporated into the modelling strategy to help understand the choices surgeons make for their patients. Longitudinal changes will be investigated allowing changes in surgeon or surgical unit performance be identified.

Models will take into account patient characteristics, and the performance of prosthesis, surgeons and surgical units can all be considered conditionally on the patient.

Scientific/Medical opportunities: Our findings will provide novel insights into factors affecting the efficacy of JRS; it will be enable researchers to identify features of prosthesis and surgical approaches which optimize patient outcomes. It will facilitate the Identification of high and low performing surgeons and surgical units to ensure the dissemination of good practice and resolution of poor practice. Our findings will allow surgeons to tailor their selection of prosthetic joints to individual patients.

The overall aim of this project is to improve patient outcomes after joint replacement surgery. Therefore the primary beneficiary of the research is the UK population that may undergo joint replacement. However, secondary consequence of improved patient outcomes includes a reduction in dependence on the health services which are associated with cost savings and increased economic activity in the general population.

The research will enable surgeons and health care providers to identify the best performing prostheses and surgical practices, ensuring patients outcomes are optimised following surgery.

Additionally policy makers will also be better able to identify high and low performing surgeons, and surgical units, enabling cases of exceptional and poor performance be investigated, allowing the dissemination of good practice and rectifying poor performance swiftly.

Findings will be disseminated and implemented by the NJR in a continuous development to improve the quality and depth of statistical analyses within the registry. Methodological developments will also be shared with other national joint registries (Australia, New Zealand, Norway, Sweden, Finland, Catalonia, Germany etc) through the NJRs membership of ISAR (International Society of Arthroplasty Registers).

I will work closely with leading academics in the applications of multi-level modelling, and experts in bone and mineral research. I will use these contacts to gain invitations to present my research at other academic institutions in the UK and abroad.

I will explore the use of workshops to illustrate the application of the methods used in the fellowship, enabling researchers in different disciplines to gain unique insights into their data through the use of advanced statistical methods.

Full details of the dissemination and engagement activities are in the 'pathways to impact' statement.