NASHVILLE, Tenn. (AP) -- Lady Gaga has canceled the rest of her tour dates due to a hip injury.
Live Nation Global Touring said in a news release that Lady Gaga has a tear in her right hip that will require surgery, followed by a recovery period.
The pop star's website showed 21 dates through March 20 remaining on her "Born This Way Ball" tour schedule. Fans who have already bought tickets will receive a refund.
Lady Gaga postponed four dates on Tuesday after experiencing difficulties Monday during her concert in Montreal. The singer's show is high energy with non-stop dancing. She explained to fans on Twitter that she'd hurt herself while performing some time ago.
A news release announcing postponements said the 26-year-old singer was suffering from synovitis, an inflammation of the joints. She underwent tests Wednesday morning that showed she had a labral tear in her right hip, however. The labrum is a layer of muscle that helps holds the ball-shaped hip joint in place. The news release says the surgery will require strict downtime.
The tour began last April in Asia and was one of 2012's highest grossing.