Posttraumatic Boutonnière and Swan Neck Deformities.

Boutonnière and swan neck deformities of the finger can be the result of trauma. The complex anatomy of the extensor mechanism of the finger makes understanding the pathomechanics of these deformities challenging. These posttraumatic deformities should not be confused with those associated with inflammatory arthritis because the treatment options are often very different. An accurate clinical assessment is essential for selecting the appropriate treatment method. Physical examination, including Elson and intrinsic-plus tests, and plain radiography are important tools for diagnosis. A variety of nonsurgical and surgical treatment modalities can be used to restore the motion of the proximal and distal interphalangeal joints and rebalance the forces across these joints. An understanding of the anatomy, clinical presentation, treatment options, and expected outcomes is crucial for optimal treatment of posttraumatic boutonnière and swan neck deformities.