What is the definition of septic arthritis?

Septic arthritis is defined as the hematogenous spread of bacteria to the synovial membrane lining the joint. This condition typically occurs when bacteria enter the bloodstream, often following a localized infection, trauma, or sometimes without an apparent source. Once in the bloodstream, these pathogens can reach the joint space, leading to inflammation, pain, swelling, and potential joint destruction if not treated promptly.

The focus on hematogenous spread highlights the pathophysiology of how infections can reach the joints, which is critical for understanding the clinical approach to diagnosing and treating this condition. Timely identification is essential, as untreated septic arthritis can result in serious complications, including joint damage and systemic illness.