Østerås, N., Moseng, T., van Bodegom-Vos, L., Dziedzic, K., Mdala, I., Natvig, B., Røtterud, J., Andreassen, Ø., Schjervheim, U.-B., Hansen, J., Vlieland, T., & Hagen, K. Implementing international osteoarthritis guidelines in an integrated care model – results from a cluster randomized controlled trial