Effect of oral erythromycin therapy in patients with aseptic loosening of joint prostheses

There is currently no cure for aseptic loosening (AL) of total joint replacement (TJR) except surgical revision. The purpose of this study was to determine whether oral EM could improve the periprosthetic tissue profiles and reduce serum cytokine production in AL patients who are candidates for surgical revision. We recruited 32 AL patients. AL patients were treated with either EM (600 mg/day, n = 18) or placebo (n = 14) daily, started one month before surgery and ending on the day of surgery. Blood samples were obtained before EM treatment and during surgery. Periprosthetic tissues and joint fluids were collected during surgery. Our results demonstrate that oral EM reduces the inflammation of periprosthetic tissues, as manifested by the reduction of the numbers of infiltrating cells, CD68+ macrophages, RANKL+ cells, and TRAP+ cells. Remarkable decreases of TNFα (9.6-fold), IL-1β (21.2-fold), and RANKL (76-fold) gene transcripts were observed in periprosthetic tissues of patients treated with oral EM. Serum levels of both TNFα and (to a lesser extent) IL-1β were significantly reduced following EM treatment (p < 0.05). Our results suggest that EM represents a biological cure or prevention for those patients who might need repeated revision surgeries and/or show the early signs of progressive osteolysis after TJR.