What is the characteristic deformity known as Swan neck deformity associated with?

Swan neck deformity is specifically associated with rheumatoid arthritis, which is an autoimmune condition affecting the joints. This deformity occurs due to a combination of hyperextension at the proximal interphalangeal (PIP) joints and flexion at the distal interphalangeal (DIP) joints, resulting in a characteristic appearance of the fingers that resembles a swan's neck.

In rheumatoid arthritis, the persistent inflammation leads to the destruction of the joint structures and surrounding soft tissues, which contributes to the imbalanced tension across the tendons that control finger movements. This condition often presents alongside other deformities and symptoms commonly seen in rheumatoid arthritis, such as joint swelling, pain, and morning stiffness.

The other conditions listed do not typically produce the same Swan neck deformity. For example, osteoarthritis generally leads to other types of joint changes, and while it can cause joint pain and stiffness, it does not commonly result in this specific finger deformity. Gout, characterized by deposits of uric acid crystals in the joints, creates a different presentation, and psoriatic arthritis has its distinct set of deformities that may include dactylitis or nail changes but not Swan neck deformity per se. Thus, the association of Swan neck deformity