Title: Lower limb arthroplasty: can we predict outcome and failure and is it cost effective?
Funder: Department of Health (England)

Abstract: Background Hip and knee arthroplasty are the most common elective orthopaedic operations performed in the NHS costing many millions of pounds per year. Although considered to be cost effective, recent evidence indicates that up to a quarter of patients a require further clinical interventions and this impact on the NHS is poorly described and the number of revision arthroplasties is set to increase. Although a number of risk factors are known for implant failure, no clinically useful model has been validated and the predictors of poor clinical outcome are poorly described. Research Plans We aim to describe the current number of hip and knee primary and revision arthroplasty using the General Practice Research Database, which contains 27,155 patients who have undergone hip and 23,536 knee joint arthroplasties since 1987 and who have records up to December 2006. The database also contains 5 age, sex and practice matched controls per case. Although the GPRD is based in primary care the database contains all of the patients’ information on clinical events, hospital referrals, hospital admissions and major outcomes. We shall next estimate the future rates of lower limb arthroplasty using predicted changes in the prevalence of osteoarthritis, rheumatoid arthritis and hip fracture, the principal determinants of lower limb arthroplasty. This data is vital for planning the future appropriate health care provision in this high volume component of the NHS. Uniquely, we shall then use clinical data from 10 existing national and hospital-based prospective arthroplasty cohort studies to validate published risk factors for poor functional outcome into an instrument to identify knees that have a high risk of complications from pre and early post-operative features. Using this data we shall also calculate the cost utility of lower limb arthroplasty and revision arthroplasty in the UK. We shall then evaluate the effectiveness of this model in a prospective cohort of arthroplasty patients to predict functional outcomes at two years. We shall recruit patients at their routine pre-operative assessment from two diverse NHS hospitals and systematically collect potential determinants in the pre- and early postoperative period. Research Team The team brings together researchers from several institutions with expertise in all of the necessary disciplines to prosecute high quality applied research including: epidemiology, outcome measures, cohort studies, biostatistics, data synthesis, health economics, arthroplasty, and NHS management. Members of the group have an excellent track record of attracting funding and of publishing in high quality journals . Research Environment The MRC Epidemiology Resource Centre, the National Orthopaedic Centre and the Wessex Institute for Health Research and Development are all internationally renowned for this type of research and have all necessary resources. Anticipated outputs The main output of this programme would be 2 simple clinical scoring systems to identify patients at a high risk of a poor surgical outcome. The first would be used to identify patients at risk during the pre-operative screening visits with the aim of identifying modifiable risk factors. The second would be applied to patients in the early postoperative period with the aim of identifying those with a high risk of poor outcome to allow early intervention. In addition to improving patients outcomes and maximising the cost effectiveness of these important surgeries, this programme would be instrumental in designs for future clinical trials in this area by identifying the potential target intervention, which patients are at most risk and therefore suitable for enrolment as well as validate appropriate outcome tools. We will also perform detailed cost effectiveness analyses for these surgeries. Public involvement The programme will be presented to the Nuffield Orthopaedic Centre Patient Forum for discussion before it is finalised. We will also have a patient representative from Arthritis Care on the steering committee. Ethical Issues The first 3 work packages have already received ethical approval. We will apply for ethical approval for work package 4 and confirm those of all cohorts studies to allow the transfer and sharing of data between centres. Justification of resources requested We have kept resources requested to a minimum. In order to work on these very large datasets, we require data managers, statisticians and research assistants. The greatest proportion of the costs is for the prospective cohort study to validate the dataset. This requires research nurses, administrative officers as well as data managers to produce high quality reliable data. We need a health economic modeller to perform the detailed economic analyses.


Research activity codes: 6.3 MEDICAL DEVICES;6.9 RESOURCES AND INFRASTRUCTURE (TREATMENT EVALUATION)
Health categories: MUSCULOSKELETAL