Osteras, N., Moseng, T., Van Bodegom-Vos, L., Dziedzic, K., Andreassen, O., Fenstad, A. M., Furnes, O., Hansen, J. N., Natvig, B., Rotterud, J. H., Schjervheim, U. B., Vlieland, T. P. M. V., & Hagen, K. B. HIGHER QUALITY OF CARE AND LESS SURGERY AFTER IMPLEMENTING OSTEOARTHRITIS GUIDELINES IN PRIMARY CARE- LONG-TERM RESULTS FROM A CLUSTER RANDOMIZED CONTROLLED TRIAL