Pathophysiology of Bone and Joint Infections

Bone and joint infections gather heterogeneous clinical situations according to numerous factors (infected site, presence of orthopedic device, infection chronicity, etc.). They occur because of traumatic inoculation, hematogenous seeding, or contiguous spread. The presence of foreign material such as implanted devices or dead bone significantly reduces the number of organisms required to cause infections and allows normal skin commensals to become significant pathogens. These infections have a dynamic environment comprised of different bone matrix qualities and cell types, in addition to the potential presence of biofilms or prostheses. Their pathophysiology implicates complex interactions between the infectious agent, host immune system, and osteoarticular tissue. It involves virulence factors at the initial phase of tissue invasion and destruction and persistence mechanisms leading to chronicity and relapse. Recent advances in experimental and clinical studies have significantly improved the understanding of bone and joint pathophysiology, which is a key factor for development of more effective diagnostic and therapeutic strategies through joint efforts of clinicians, scientists, and engineers.