PAPrKA: Physical Activity Patterns after Knee Arthroplasty 

Knee Osteoarthritis (OA) is a degenerative knee joint disease that affects around 250 million people globally. That means one in five people aged over 50 in the UK are affected.  

OA can be treated with an operation called a Knee Arthroplasty, also known as joint replacement. During this operation the damaged knee surfaces are replaced to reduce pain in patients and improve mobility. Before their operation, patients want to know how long their recovery will take and how much mobility they will regain. 

Our study, led by The University of Manchester, will answer those questions. To do this we’ll use the vital data our patients will share with us from their smartphones and wearable fitness devices. 

Project aims 

The Physical Activity Patterns after Knee Arthroplasty (PAPrKA) study is aiming to do three things: 

• To understand physical activity in people with knee osteoarthritis before and after joint replacement. 

• To understand factors that might influence different recovery pathways. 
• To share our findings about how to work successfully with people and access and link their data for research. 

Latest updates

1. When did you have a knee replacement?

November 2022 – this was a partial knee replacement and followed a microfracture procedure on the same knee 5 years previously

2. Can you describe what daily life was like for you prior to the surgery?

It was becoming increasingly difficult. Standing was painful. I was unable to move anywhere quickly and had to give up most of my active lifestyle (certainly no running, and country walks became more and more limited). My job as a teacher required me to be on my feet for most of the day – teaching, moving around school, daily duties and so on – and each day my knee would become progressively more swollen and painful throughout the day. Walking downstairs and down any kind of slope was especially difficult. Colleagues would worry about me and ask if I was alright; this was especially difficult as I still mentally saw myself as a fit and active person, but the daily reality was that I was becoming more and more restricted.

3. What made you decide to have surgery?

It was a combination of factors:

• The realisation that I was in a worse state than I realised – I was being stoic and assuming there were plenty of people suffering far more than I was.
• A friend in my running club who had similar problems and whose life had been transformed by having surgery.
• A ‘final straw’ moment – we were on holiday visiting Bath and were taking part in a guided walk around the city – not very far or very fast but my knee became so painful I had to abandon the tour and limp back to our hotel. I realised that the increasing limitations to my movement would jeopardise my physical fitness and wellbeing and I would be at risk of becoming a greater burden on the health service as well as losing much of what gave me a good quality of life.

4. How has your daily physical activity changed since having the surgery?

It improved dramatically – I no longer experienced the swelling and pain I had previously had, and I was able to resume much of the active elements of my life before my knee issues developed. Long walks, moving around quickly, and no longer having to stop and think about whether I could do something. In terms of my overall health, I feel fit and healthy and able to maintain a level of activity that supports my health. The positive effect on mental health cannot be underestimated – as an active person, the ability to maintain an active lifestyle is crucial for my own mental wellbeing.

5. Were you told how quickly your mobility would improve?

I had an amazing surgeon who adopted a positive approach throughout the process. He made it clear that I had to follow the post operation exercises properly but essentially said I could do as much as I was prepared to do, and that with common sense I shouldn’t restrict what I wanted to do. The expected recovery period was 6 months and by this stage, I really did feel back to normal. It is now 3 years since my surgery and I am able to walk and cycle long distances without too much hindrance. I know where the limits are and can recognise when my knees (as well as the rest of me!) need time to recover.

6. Why do you think this study is important for people like yourself?

For many people, the activity we do is based on what we are required to do and what we feel able to do, but the availability of data can really bring home the extent to which your mobility is changing. I was managing and coping with my job but when I looked at the extent of my activities (variety, distances, frequency, heart-rate, etc.) on my activity tracking, it was starkly evident how much this had been curtailed. Post operation it has been a great motivator to see how I have been able to improve and increase these elements, as well as alerting me to when I might be pushing things too far. My hope is that PAPrKA can give people like me a clearer understanding before surgery of how much better their activity is likely to get. As someone who tracks and analyses my activities, the data this provides really helps decision making in the nature and extent of activity that is possible.