His knee dislocates and it is very uncomfortable.???To The Sun???s TV Biz, the insider added, ???He???s had physio sessions for years but the pain persists so surgery is the best solution to have him fully fit and ready for the demands of a long tour.???Last year, Niall spent weeks on crutches because of his knee, and at the time, he joked that a squirrel attack had damaged his leg.But of the surg