His silver medal at the 1980 IAAF World Cross Country Championships made him only the second German to win an individual medal at the competition, after 1977 bronze medallist Detlef Uhlemann. Orthmann's finish remains the best ever by a German athlete. Orthmann was consistently among the best performing West German men at the competition in the 1970s and 1980s, scoring points for team alongside others including Michael Karst, Christoph Herle, Michael Scheytt and Ralf Salzmann. Their best finishes in the team competition were fourth place, achieved in 1977 and 1979.