From the official press release we recieved yesterday:

Live Nation Global Touring has confirmed that the remainder of the Lady Gaga Born This Way Ball performances have been cancelled.  That includes the South Florida shows that were scheduled for March 15th and 16th at BB&T Center and AmericanAirlines Arena.

After additional tests this morning (2/13) to review the severity of the issue, it has been determined that Lady Gaga has a labral tear of the right hip.  She will need surgery to repair the problem, followed by strict down time to recover.   This unfortunately, will force her to cancel the tour so she can heal.  
 
Refunds for the cancelled performances will be available at point of purchase starting Feb 14, 2013.