What condition is best associated with joint stiffness and swelling, particularly in the morning?

The condition most closely associated with joint stiffness and swelling, particularly in the morning, is rheumatoid arthritis. This autoimmune disorder primarily affects the synovial joints, leading to inflammation, pain, and swelling. One of the hallmark features of rheumatoid arthritis is the occurrence of morning stiffness that lasts for more than one hour. This is due to the inflammatory process that is more active after periods of rest, which can lead to significant discomfort and decreased range of motion upon waking.

Additionally, individuals with rheumatoid arthritis often experience symmetrical joint involvement, where the same joints on both sides of the body may be affected, and over time, this can lead to joint deformities if not adequately managed. In contrast, conditions such as osteoarthritis primarily involve stiffness that may improve with movement and do not typically present with prolonged morning stiffness. Muscle strains and gout can cause joint pain and swelling, but they do not exhibit the same pattern of morning stiffness associated with rheumatoid arthritis. Thus, the characteristics of joint stiffness in the morning strongly point to rheumatoid arthritis as the correct answer.