Nonetheless, Quin et al. [22], in a prospective study, recruited 102 patients with joint pain after arthroplasty, i.e., 39 patients with aseptic prosthesis loosening, 26 patients with acute rheumatoid arthritis (RA, n = 26) and 37 patients suffering from PJI, and demonstrated that current synovial IL-6 levels do not accurately rule out the presence of PJI in patients suffering from RA and complaining of a painful THA or TKA. This evidence concerns the gene IL6 and rheumatoid arthritis.