Feasibility of Good Boost+ for Adults Awaiting Total Knee Replacement

The goal of this randomised controlled feasibility trial is to find out whether it is possible to run a larger study of the Good Boost+ community based rehabilitation programme for people waiting for a primary total knee replacement. The study will look at how many people are willing to take part, whether they stay in the study, and whether they can follow the Good Boost+ programme as planned. It will also explore how acceptable the programme is to patients, NHS staff and leisure centre staff, and which outcome measures are most useful for a future full scale trial. The study will also look at what helps or hinders delivery of the programme in real world NHS and community settings. The main questions it aims to answer are: * How many people waiting for knee replacement surgery are willing to take part in the study * Whether participants can continue with the Good Boost+ programme as planned over the study period * Which outcome measures best capture any potential benefits of the programme * How acceptable the programme is to patients, NHS and leisure centre staff * What helps or makes it difficult to deliver the programme in practice. Participants will be randomly assigned to one of two groups. * Usual NHS care or * Usual NHS care plus the Good Boost+ programme Participants in the Good Boost+ programme will take part in six weekly group water based exercise sessions held in local swimming pools, as well as land based exercise sessions that can be done individually or by joining a virtual group. The exercise sessions are delivered through Good Boost's digital technology, using small waterproof tablet computers at swimming pools, and smartphones or computers for land-based sessions. Physiotherapy staff will provide guidance throughout, and volunteers will offer refreshments after pool sessions to support social connection. All participants, including those receiving usual NHS care only, will be asked to complete an exercise diary, rate their knee pain each week, and complete short questionnaires at 6 and 10 weeks after joining the study.