Loretta Lynn has postponed a few concerts, due to a torn knee ligament that requires minor surgery.

Venues including Philadelphia's Temple Performing Arts Center and Washington, D.C.'s 9:30 Club are telling ticket holders that the 78-year-old country legend must reschedule for a later date.

"She regrets disappointing any of her fans, but looks forward to rescheduling her shows as soon as possible," a spokesperson for Loretta tells The Boot.

At a concert on March 4 in Buffalo, New York, Loretta told the crowd of her knee pain and asked their permission to continue the show while seated. At one point during her performance, the audience could sense Loretta was steeling herself against the pain, wrote a journalist for the Buffalo News. Loretta held the hand of her son, Ernest Ray, as she got out of the chair to sing a medley of gospel songs before closing the show with 'Coal Miner's Daughter.'

She also took a seat on stage -- after about 15 minutes of standing -- at a recent concert in Greensboro, N.C., according to a journalist at Yes! Weekly, who also reported Loretta told the crowd the shoulder on which she had surgery in 2006 was giving her trouble that night.

Loretta's packed concert schedule, in sickness and in health, is not unusual for the music icon. She performed shows until just a few days before she underwent knee surgery in 2000. And she kept performing in 2009 after a bad bout with the flu, telling Billboard she was "feeling great."

Loretta received many honors last year when she marked her 50th Anniversary in show business, and the accolades keep coming. On April 4, she will be among those honored at 'Girls' Night Out: Superstar Women of Country - the Concert of the Year,' at the MGM Garden Arena in Las Vegas.