Lady Gaga was forced to postpone four U.S. concerts earlier this week. Now a "labral tear of the right hip" has the 26-year-old canceling the remainder of her Born This Way Ball tour, set to continue through mid-March. Gaga will require surgery followed by "strict downtime." After the initial batch of postponed dates, Gaga wrote, "I've been hiding this injury and pain from my staff for a month, praying it would heal, but after last night's performance I could not work." Ticket holders will be refunded.