Table 1 Trial inclusion/exclusion criteria

Meet the National Institute for Health and Care Excellence (NICE) osteoarthritis clinical criteria [8]:

 - aged 45 years and over

 - activity related knee joint pain

 - morning stiffness ≤30 min

Booked for knee joint replacement surgery;

History of knee pain on most days for ≥3 months

Have had a knee joint replacement in the most painful knee

Overall average knee pain in past week self-rated as ≥4 out of 10 on an 11-point numeric rating scale (NRS)

Have participated in a structured knee exercise program within the past 6 months

Able to give informed consent and to participate fully in the interventions and assessment procedures

Self-reported diagnosis of rheumatoid arthritis or other inflammatory arthritis

Have a mobile phone with text message functioning and be willing to use it during the study to receive and send text messages

Have had a fall within the last 12 months and do not receive clearance from a General Practitioner to participate in an unsupervised home exercise program

Have a home Internet connection and a device that enables access to the Internet.

Are housebound requiring assistance from another person to leave the house in the previous month and do not receive medical clearance from a General Practitioner to participate in an unsupervised home exercise program

Fail pre-exercise screening [73] and do not receive medical clearance from a General Practitioner to participate in an unsupervised home exercise program

Unable to speak or read English