Total hip and knee replacement surgery are two of the most common orthopaedic operations performed worldwide. By 2030 it has been estimated that the demand for primary total hip replacement is expected to increase by 174 per cent globally.

Approximately 50 per cent of people who have a hip or knee replacement have two or more other diseases (such as high blood pressure, diabetes, depression or cardiovascular disease). These are all diseases whose impact on individuals can be reduced through physical activity. It has been suggested that people should be more active after a joint replacement since this operation is successful at improving joint movement, reducing pain and decreasing overall disability. However our research since 2014 has questioned whether this is true.

Our team have undertaken a series of studies investigating firstly the degree of physical activity after hip or knee replacement and secondly what factors may influence why someone is (or is not) physically active following a hip or knee replacement. This is important as physical activity can have a significant beneficial effect on an individual’s health and well-being as well as on society as whole.

Key Research Questions

The overarching research questions of this work:

  • Are people more/less/at the same level of physical activity before compared to after a hip or knee replacement?
  • What factors impact on whether someone is more, less or at the same level of physical activity after a hip or knee replacement compared to before?
  • What interventions could improve physical activity participation for people who are not physically active, following a hip or knee replacement?

Research Design and Outputs

To answer these research questions, we have undertaken a number of different studies. We have reported on observational study data and epidemiological analyses on how physical activity behaviours and levels change before and after a hip or knee replacement. Taking large cohorts of individuals from both the UK and USA, we have been able to identify what this change is, and specific groups of people in whom this change is more or less likely to occur after a hip or knee replacement.

We have undertaken systematic reviews with quantitative (meta-analysis) and qualitative (meta-ethnography) assessments to explore how physical activity does (or does not) change following hip and knee replacement. We have also been able to identify what factors affect whether an individual is more or less likely to be active after this operation, determining barriers and facilitators to physical activity participation from different populations across the world. These have provided new understanding on what could be done to promote and foster physical activity behaviours in this population.

Through this work we received funding from the UK National Institute for Health Research to undertake a trial to explore an intervention to promote physical activity participation in this population. This was conducted with the University of Oxford’s Clinical Research Trials Unit in the Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences (NDORMS). This multi-centre randomised controlled trial (PEP-TALK) explored, across nine hospitals in England, the effectiveness of routine physiotherapy versus physiotherapy with a physical activity behaviour change intervention. Over 220 people following hip and knee replacement were recruited over the 12-month trial. The results have been reported in the BMJ Open journal.

The Research Team

Principal investigator: Dr Toby Smith (University of East Anglia)

UEA Team: Professor Alex MacGregor and Dr Jack Dainty

External collaborators: Dr Tom Withers (University of Birmingham), Professor Cath Sackley (University of Nottingham).