What is It?
Swan neck deformity is caused by abnormal stress on the volar plate, the ligament around the middle joint of the finger (PIP joint). The resulting shape of the finger looks similar to a swan’s neck, which is how the condition got its name.
What is it caused by?
For a swan neck deformity to occur, abnormal stress must be put on the ligament around the PIP joint of the finger. The stress causes the ligament to loosen, which then causes hyperextension of the PIP joint. As a result, the PIP joint bows. Simultaneously, the joint furthest from the palm (DIP joint) droops down.
This condition can be caused by rheumatoid arthritis, an untreated volar plate injury, an untreated mallet finger injury, or by other direct trauma to a finger that has weakened ligaments surrounding the PIP joint.
How is it treated?
Swan necking is treated with custom made splints (see figures 1 & 2) which correct the position of deformity. The aim of splinting after injury is to allow the loose/lax PIP joint to tighten up and become more stable. The aim of splinting for arthritis is to improve hand function. Many newer styles of splints resemble jewellery and have been designed so they can look discrete or decorative.