Plasma Cytokines as Markers of Aseptic Prosthesis Loosening

The proinflammatory cytokines IL-1β, IL-8, and TNF-α play a major role in the process of bone resorption during aseptic loosening of large joint prostheses. These cytokines secreted locally during bone resorption in aseptic loosening may enter peripheral circulation. Increased concentration of IL-1β, IL-8, and TNF-α in peripheral circulation may indicate aseptic loosening. We determined whether bone resorption could be verified by cytokine presence in plasma. We recruited 50 patients with aseptic prosthesis loosening, 50 with stable prostheses, 50 with osteoarthritis, and 50 healthy individuals. Cytokine levels were determined in plasma by ELISA tests. Patients with prosthesis loosening had higher plasma levels (IL-1β, 3.7 ± 5.5 pg/mL; IL-8, 14.7 ± 9 pg/mL; TNF-α, 32.7 ± 32.4 pg/mL) than patients with stable prostheses (IL-1β, 1.5 ± 2 pg/mL; IL-8, 8.1 ± 4.7 pg/mL; TNF-α,22.9 ± 18.7 pg/mL), patients with osteoarthritis (IL-1β,0.7 ± 1.1 pg/mL; IL-8, 5.8 ± 3.8 pg/mL; TNF-α, 9.8 ± 7.7 pg/mL) and healthy individuals (IL-1β, 0.7 ± 1.1 pg/mL; IL-8, 4.2 ± 1.3 pg/mL; TNF-α, 3.9 ± 3.9 pg/mL). Our data suggest elevated plasma levels of proinflammatory cytokines may be useful as markers of bone resorption in the laboratory diagnosis of prosthesis loosening.

Level of Evidence: Level IV, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.