 Fladberg won the gold medal at the 1983 IBF World Championships in men's doubles with Jesper Helledie, defeating Mike Tredgett and Martin Dew 15-10, 15-10 in the final.He was a silver medalist at the same tournament in mixed doubles with Pia Nielsen.He also won at the 1986 European Badminton Championships in men's doubles with Helledie, and the 1988 European Badminton Championships in mixed doubles with England's Gillian Clark.