Managing Swan Neck and Boutonniere Deformities.

Acute and chronic injuries to the finger extensor mechanism can result in swan neck and boutonniere deformities. Loss of coordination between the multiple, specialized components of the extensor mechanism results in tendon imbalances leading to altered interphalangeal joint flexion and extension forces. Treatments include corrective splinting and operative interventions. Swan neck deformities are functionally limiting. Surgical correction generally results in functional benefit. Boutonniere deformities are functional but aesthetically displeasing; proximal interphalangeal (PIP) joint flexion and the ability to make a fist are maintained. Surgical improvement can be attempted with caution. Attempts to improve PIP extension can impede flexion, resulting in a poor functional outcome.