Agree with Pam about radio exposure. I've found it an easy and effective (depending on the popularity of the show) way to get the word out. Plus, it's free, and I usually don't even have to get out of my p.j.'s!

Also, consider e-mailing Jane Brody, a Health editor at the NY Times, a personal note telling her about your book. Then follow up with a copy of the book and a press kit. Last Tuesday in the Science section she wrote movingly about her ordeal having a double knee replacement. web page She's still suffering. I think she'd be interested, and she's in a great position to pass the word along. You might want to pitch to the Science Times book editor as well.