Pope Francis said in an interview this week that he would be undergoing a small medical procedure, “an intervention with infiltrations,” to provide some relief.
Therapeutic injections are sometimes used to relieve knee pain caused by ligament tears.
The pope’s movements have been visibly more limited for months.
During an April 2-3 visit to Malta, extra measures were taken to ensure that the pope would not have to take stairs, due to his knee problem.