Previous research has shown that the osteoarthritis care for persons with hip or knee osteoarthritis in Norway has a potential for improvement as the provided care may not necessarily reflect evidence-based guideline recommendations. This study will determine if a new model for integrated osteoarthritis (OA) care in primary health care will result in improved quality of osteoarthritis care and health benefits for the patients (reduced pain and body weight, increased function and activity level) among patients with hip and/or knee osteoarthritis. Further, this study will examine if the new model reduce the number of unnecessary referrals to Magnetic Resonance Imaging (MRI) and to orthopaedic surgeons in secondary care, and if it increases the number of referrals to physiotherapy treatment and the number of discharge reports from the physiotherapists to the referring general practitioner.

A new model for integrated care for patients with hip and/or knee osteoarthritis (OA) in primary care will be developed and implemented. The purpose of the model is to improve quality of OA care in primary health care services by increasing the collaboration between health care professionals and across health care levels, providing an integrated care and a patient pathway, and facilitating an active and healthy lifestyle among individuals with OA. This implementation study represents a collaborative study between six municipalities and a hospital department aiming to fulfill the intentions of the Norwegian Health Care Coordination Reform. The main aim of the present study is to implement and perform process and effect evaluations of this new model for integrated OA care. The study design will be a cluster randomized controlled trial with a stepped wedge design. Six neighboring municipalities will constitute the six clusters, which will switch from control (current OA care) to intervention phase (new OA model) in a randomized order. All municipalities start the trial simultaneously and act as controls until the point in time they are randomized to crossover from control to intervention, and all municipalities have implemented the intervention by the end of inclusion. The method consists of two parts; 1) Identification of barriers/facilitators + development of the model and interventions, 2) Implementation of the new model (interactive workshops) with process and effect evaluations. Participants will be general practitioners and physiotherapists in primary care as well as people with hip or knee OA.

Inclusion Criteria:

• Activity-related hip and/or knee pain/complaints AND
• Clinical signs and symptoms corresponding to hip and/or knee OA OR radiologically diagnosed OA OR Registered in the medical journal with the ICPC codes L89 (osteoarthritis of the hip), L90 (osteoarthritis of knee), L91 (osteoarthritis not classified elsewhere), L13 (hip symptoms/complaints), L15 (knee symptoms/complaints) and/or L20 (joint symptoms/complaints not classified elsewhere).

Exclusion Criteria:

• Total hip or knee replacement in the actual joint(s) and no pain/complaints in the other hip or knee joint(s)
• Inflammatory rheumatic diseases (e.g. rheumatoid arthritis, spondyloarthritis)
• Malignant illness or other major conditions (i.e unstable cardiovascular disorders or lung disease, dementia) that restrict the ability to adhere to the recommended OA treatment
• Do not understand the Norwegian language