Remote Monitoring After Knee Replacement Surgery

Participants are eligible for inclusion in the study if the following criteria apply:

* men and women, 50 years of age or older * referred to total or unicondylar (medial) knee replacement surgery due to knee osteoarthritis

Participants are excluded from the study of any of the following criteria apply:

* revision of previous knee replacement surgery * serious comorbidities (such as severe malignancues, severe diabetes mellitus, severe infections, uncontrollable hypertension, severe cardiovascular disease, severe respiratory disease) * congnitive dysfunction * knee replacement surgery due to trauma or inflammatory joint disease (such as psoriatic arthritis or rheumatoid arthritis) * unable to understand Norwegian * Cannot answer questionnaires digitally (lack BankID, do not possess a smartphone * deemed inappropriate for remote monitoring by orthopedic surgeon

Patients included in both treatment arms will receive medical treatment according to current treatment recommendations as applied by the treating orthopedic surgeon after total knee replacement. All partients are recommended to seek physiotherapy treatment in primary care after surgery

Patients randomly allocated to the control group will be summoned for a hospital visit with a physiotherapist at 2 and 12 months. The physiotherapist will conduct assessment in line with regular clinical practice. If the patient is experiencing lack of improvement or adverse events, an orthopedic surgeon may be consulted. The patients will also answer patient-reported outcomes at 8 weeks and 6- and 12 months post-surgery, however, these answers will not be monitored.

Patients randomly allocated to the remote monitoring group will answer patient-reported outcome at 1, 2, 3, 6 and 12 months. They will be provided with a brief introduction from the study personnel on how to answer questions remotely through the Youwell platform. Patients will get an SMS notification on their mobile phone with a link to the questionnaire. They will have to log in with BankID to access the questionnaire. A physiotherapist will monitor the answers and will contact the patient if an unexpected deterioration or adverse events are detected.

Data will be collected through Nettskjema or the Youwell/Dignio software program and will be stored in Services for Sensitive Data (TSD) and a a secure server at Diakonhjemmet Hospital.

The following data will be recorded through self-report in the baseline questionnaire:

* Demography: mobile number, education, work status, living arrangement, socioeconomic status, social support, expectations about treatment, fear of movement, catastrophizing, self-efficacy * Disease variables: KOOS, other joints with osteoarthritis, duration of complaint, previous treatment, fatigue, disease activity, pain, function, pain medication, osteoarthritis quality indicators, knee flexion/extension, use of walking aids * Lifestyle variables: physical activity, motivation for exercise, motivation for surgery * Health competency, digital self-efficacy * Patient satisfaction * Health-related quality of life The following information will be collected from medical records * Demographic variables: Age, gender, height, weight, comorbidity, referred knee, smoking, * General medical history: description of radiographs, type of scheduled arthroplasty, joint status prior to surgery

Patients allocated to the remote monitoring group will receive an SMS with link to questionnaires in the Youwell/Dignio platform at 1, 2, 3, 6 and 12 months. The following data will be collected for the remote monitoring group:

* Global rating of change * Pain/Pain medication * Fear of movement * Expectations about treatment * Disease activity * Signs inflammation/swelling * Function/activity * Knee flexion/extension * Use of walking aids * Exercise * Contact with physiotherapist/ rehabilitation stay * Adverse events * Patient satisfaction with care

A highly experienced physiotherapist will review the answers and based on these make a clinical judgement whether there is a need to call the patient or summon the patient for a physical examination, or if the patient seems to manage well at home.

Patients in the control group will also answer the remote monitoring questionnaire at 2 months, however, their answers will not be monitored (just for research purposes).

At follow-up, the following variables will be collected:

* Global rating of change * Disease variables: KOOS, fatigue, disease activity, pain, function, pain medication, * Fear of movement * Self-efficacy * Knee flexion/extension * Lifestyle variables: physical activity, * Patient satisfaction with care * Health-related quality of life * Health care costs: hospital stay, rehabilitation stay, travel distance to hospital, transportation, health care use * Adverse events

• OMERACT-OARSI responder criteria [Time frame: Baseline, 12 months]
• Healthcare costs [Time frame: Baseline, 6 and 12 months]
• Health-related quality of life (EQ5D-5L) [Time frame: Baseline, 6 months, 12 months]
• Safety measures [Time frame: 1 month, 2 months, 3 months, 6 months, 12 months]
• Change in Knee Injury and Osteoarthritis Outcome Score (KOOS) [Time frame: Baseline, 6 months, 12 months]
• Change in pain [Time frame: Baseline, 2 months, 6 months, 12 months]
• Change in disease activity [Time frame: Baseline, 2 months, 6 months, 12 months]
• Satisfaction with care [Time frame: 2 months, 6 months, 12 months]
• Satisfaction with total knee replacement surgery [Time frame: 2 months, 6 months, 12 months]
• Change in range of motion [Time frame: Baseline, 1, 2, 3, 6, 12 months]
• Number of extra visits [Time frame: Baseline to 12 months]