**Core Concept**
Clutton's joint refers to a form of chronic proliferative synovitis, a type of arthritis characterized by inflammation of the synovial membrane in the joints, particularly the knees. This condition is associated with a specific underlying disease process.

**Why the Correct Answer is Right**
Clutton's joint is commonly seen in patients with congenital syphilis, a condition resulting from the transmission of Treponema pallidum from mother to child during pregnancy. The infection leads to the production of autoantibodies that cause inflammation and proliferation of the synovial membrane, resulting in joint pain and swelling. The synovial membrane becomes thickened, and the joint space is filled with fluid, leading to a characteristic "bubbly" appearance on radiographs.

**Why Each Wrong Option is Incorrect**
**Option A:** This is incorrect because Clutton's joint is not typically associated with rheumatoid arthritis, which is a different type of autoimmune arthritis.
**Option B:** This is incorrect because osteoarthritis is a degenerative joint disease that is not linked to Clutton's joint.
**Option C:** This is incorrect because septic arthritis is an acute infection of the joint, whereas Clutton's joint is a chronic condition.

**Clinical Pearl / High-Yield Fact**
Clutton's joint is a classic sign of congenital syphilis, and its presence should prompt further investigation for this underlying condition.

**Correct Answer: D. Congenital syphilis**