The Gut Microbiome as a Novel Pathogenic Mechanism in Loosening of Orthopedic Implants

16S rRNA sequence data. Particles released from implants cause inflammatory bone loss, a key factor in aseptic loosening, which is the most common reason for joint replacement failure. With the anticipated increased incidence of total joint replacement in the next few decades, implant loosening and failure will continue to burden patients both physically and economically. Although the gut microbiome is increasingly recognized as an important factor in bone physiology, its potential role in implant loosening is currently unknown. The gut microbiome is affected by injuries and changes in systems remote from the gut, including burns to the skin, stress and disrupted circadian rhythm. We tested the hypothesis that implant loosening is associated with changes in the gut microbiome in a preclinical rat model of particle-induced implant loosening. When the particle challenge caused local joint inflammation, decreased implant fixation and decreased peri-implant bone volume the gut microbiome was also affected. Our results support the hypothesis that a particle challenge leading to diminished implant fixation alters the gut microbiome. While there is growing evidence that manipulating the gut microbiome can affect the skeleton, our data suggest that the implant microenvironment affects the gut, which raises the possibility that cross-talk between these compartments may be a previously unrecognized mechanism of failure following total joint replacement. If correct, then treatments that dampen communication in either direction between the gut and implant microenvironment may prove useful in preventing or delaying implant failure.