Chief Justice William H. Rehnquist canceled a speech in Alabama yesterday after falling and injuring his knee at home.

Supreme Court spokeswoman Kathy Arberg said Rehnquist was treated at a Washington-area hospital after hurting himself Thursday night. "He's fine, but he injured his knee and couldn't make the trip," she said.

Arberg said that the injury caused swelling from excess fluid and that Rehnquist must use crutches. She did not know other details about the accident or the expected length of his recovery.

Rehnquist, 78, was scheduled to speak to law students at the University of Alabama in Tuscaloosa. The university was notified yesterday morning that he would not make the trip.

The chief justice, a widower, has served on the high court 30 years and as chief justice since 1986. He is the second-oldest of the justices and has been in generally good health, although he suffers from back problems and had back surgery in 1995.

Justice John Paul Stevens, the oldest at 82, has had prostate cancer. Justice Sandra Day O'Connor had breast cancer, and Justice Ruth Bader Ginsburg had colon cancer.

Rehnquist planned to spend part of the weekend in Tuscaloosa attending the Alabama-Auburn football game, a matchup of intrastate rivals.

More than 400 people were expected at his speech, which school leaders hope to reschedule.

"We fully understand the chief justice's health comes first. We wish him a speedy recovery," said Kenneth Randall, the law school dean.

Chief Justice William H. Rehnquist stayed home from a planned speech and football game in Alabama after a fall injured his knee.