Zsa Zsa Gabor had no leg, and no clue. The bedridden Hollywood icon — whose right leg was amputated above the knee last year — was never told about the surgery, her husband, Prince Frederic von Anhalt, admits. “It took over a half a year” for Gabor, 95, to make the gruesome discovery on her own, the actress’ ninth husband told The Post at a fund-raiser for the Brent Shapiro Foundation in Los Angeles. “She found out about it when she told me to sit her up, and she saw it. She couldn’t feel it because [one] hand is paralyzed and [one] hand was too short to go on it . . . Finally, a half-year later she said, ‘There is something missing.’ ” That isn’t the only secret her husband of 26 years has kept. Von Anhalt — accused by his daughter-in-law Francesca Hilton of keeping the actress “increasingly isolated” — continued, “She doesn’t even know she gets food through the tube. It will only upset her. She was so glamorous always, and she is so vain.” He also admits of the death of her