This study is looking at the how the use of non-immersive virtual reality technology can be used to help people that have pain in their knees caused by osteoarthritis. It is a feasibility randomised controlled trial to investigate the feasibility of the use of the intervention by patients in their homes in a larger randomised controlled trial.

The intervention is a non-immersive virtual reality system. This involves sensors that are strapped to the user's arms, legs, head, or chest (depending on the specific exercise). Their movement then controls a character on the screen of either a laptop or a TV. Patients then work through a series of games that replicate physiotherapist exercises. Their performance in the games determines the difficulty of the games, and as patients improve, the exercises get harder. Patients are required to perform these exercises 3 times a week over 12 weeks. During this time, patients have the opportunity to attend clinics with a physiotherapist to review their progress. This intervention is being compared to standard care physiotherapy exercises that patients perform at home in their own time. This programme is prescribed to them by a physiotherapist, and they are followed up regularly over 12 weeks as they perform the programme at home.

This is a feasibility study, and has no single primary outcome or objective. Instead, there are several main outcomes and objectives related to the feasibility of the study and the intervention. The feasibility of recruitment to the study will be measured by the ability to achieve a recruitment of 4 patients per month, over 13 months. The recruitment target is 50. Patient willingness to be randomised will be measured by the reasons for non-consent and withdrawal given by patients. The completeness of outcome measures is measured by the of questionnaires and outcomes completed at 12- and 24-weeks post randomisation. The fidelity of healthcare professionals delivering the intervention will be measured by treatment logs for face-to-face contact, and the observation of two assessments for setting up knee osteoarthritis patients with the intervention. The acceptability of intervention and trial procedures to participants will be measured by interviews with patients and staff about expectations and experience of the intervention, and barriers and facilitators to trial participation. Adverse events experienced by participants from the intervention and trial procedures will also be measure by treatment logs. Adherence to the physiotherapy programme will be measured by the number of times and when patients logged in to the VR games and if follow up consultations were used. There are a variety of secondary objectives and outcome measures. A variety of measurements relating to muscle strength and endurance, aerobic capacity, exercise technique, central pain processing, and self-reported pain mechanisms and moderators will be used to understand how the exercises work to improve pain outcomes. The ability of the intervention to treat knee osteoarthritis will be measured by the OMERACT-OARSI core domain set, a variety of patient-reported outcome measures, pain sensitisation by algometer, and a dynamic balance using a step test.

The target population is adults with knee osteoarthritis who fulfil the NICE and ACR criteria for knee osteoarthritis diagnosis and who have been referred to a physiotherapy clinic.