“…3,4 The rate increases to between 0.2 and 21% when the knee prosthesis includes a patellar replacement. 3,5 Patellar fractures can be caused by direct injury or a stress fracture, 1,6,7 mostly in TKAs. 5,[8][9][10] In TKAs without patellar resurfacing, patellar fractures are usually caused by rheumatoid arthritis or degenerative osteoarthritis.…”