What is the most common location for septic arthritis to occur?

Septic arthritis most commonly occurs in the knee or hip due to the large joint size and the presence of abundant synovial fluid, which provides an ideal environment for bacterial growth. The knee, in particular, is a frequent site for infections that lead to arthritis because it is a major weight-bearing joint, often subjected to trauma and stress which can predispose it to infection.

In contrast, while joints such as the elbow, wrist, ankle, and shoulder can certainly be affected by septic arthritis, they are less commonly involved compared to the knee and hip. The hip is also a significant site for septic arthritis, especially in children and the elderly, due to factors like hematogenous spread of infection or underlying conditions. The incidence in these larger joints is also influenced by the vascular supply and the immune response, impacting susceptibility to infection.

Therefore, the knee and hip are consistently recognized as the most prevalent locations for septic arthritis, reflecting the critical role of joint anatomy and pathogen dynamics in determining infection sites.