Experimental: App-based model of care

The app-based model of care includes at least one physical visit at the clinic. The majority of the treatment is provided by the app, containing five different sections:~1\) My information: specific information regarding osteoarthritis and generic lifestyle advice. 2 \& 3) My exercise \& My plan: individualized exercises where instructions are given through real-time video or pictures and written descriptions. The patient has access to a calendar and an overview of scheduled rehabilitation/exercises and care meetings. 4) My progress: weekly assessment of pain + every six-month with valid patient reported outcome measures and test of function. 5) My messages (asynchronous chat with the responsible physiotherapist). The app sends automatic and daily reminders and / or motivational notifications.

Active_comparator: Web-based model of care

The patient will get access to information about osteoarthritis and generic osteoarthritis exercises program from a web-based platform Individualization of the training can be done by the responsible physiotherapist informing about changes in the training via the message function and / or during physical follow-up visits. An individualized rehabilitation program can be given to the patient, via the platform or at a physical visit at the clinic, in form of a document with pictures and descriptive information. As long as the patient is under treatment (approximately three months), he/she can contact their responsible physiotherapist by sending a message from the platform.

Active_comparator: Standard care

Patients who are randomized to standard care receive osteoarthritis specific information at three different group meetings (physical or digital) led by a physiotherapist, an occupational therapist and / or dietitian (each rehab clinic makes its own arrangement). After the theory sessions, the patient is booked for another physical visit to the responsible physiotherapist where an individual training program is tested. The patient is then offered to regularly exercise at the clinic, individually or in a group under supervision from a physiotherapist.