Which condition is characterized as inflammatory arthritis of large joints and is a post-infectious complication?

The selection of reactive arthritis is correct because this condition specifically arises as a post-infectious complication, often following a genitourinary or gastrointestinal infection. Reactive arthritis is an inflammatory type of arthritis that primarily affects large joints, such as the knees and ankles, and typically develops in response to an infection elsewhere in the body. This can occur even after the initial infection has resolved and is characterized by inflammation triggered by the immune response rather than by direct infection of the joints.

In contrast, the other conditions listed do not fit the specific criteria provided in the question. Rheumatoid arthritis is an autoimmune disorder that involves chronic inflammation of joints but is not directly a post-infectious complication. Systemic lupus erythematosus is another autoimmune condition that can affect joints but does not qualify as inflammatory arthritis that follows an infection. Osteoarthritis is primarily a degenerative joint disease related to wear and tear rather than an inflammatory response to infection. Consequently, reactive arthritis distinctly aligns with both the inflammatory and post-infectious elements described.