Swan neck deformity: a review of its causes and treatment options

Swan neck deformity is characterized by hyperextension of the proximal interphalangeal joint and limited extension of the distal interphalangeal joint, showing the shape of a swan’s neck. The deformity can occur either acutely or chronically. A common acute cause of this deformity is trauma, and a common chronic cause is a secondary deformity due to rheumatoid arthritis. The treatment of swan neck deformity tends to depend on the knowledge and experience of the physician because the number of cases that hand surgeons can experience is limited, and there are no clear guidelines on treatment options. This review introduces the known causes of swan neck deformity and its treatment options. For swan neck deformity, the cause of the deformity, the elapsed time, the stage of the deformity, the biomechanical relationship between adjacent joints, and the functional limitations and needs of the patients must be considered when determining the treatment method. Based on these considerations, an appropriate choice should be made between nonsurgical and surgical treatment. The patients should receive a full explanation before treatment that an optimal outcome is not always guaranteed. The treatment process requires full understanding and cooperation from the patient.