Swan-Neck Deformity

On examination, joint swelling may be visible or may be apparent only by palpation. The tissue feels soft and spongy and may appear erythematous and warm, especially early in the course of the disease. Chronic joint deformities commonly involve subluxations of the wrists, metacarpophalangeal joints, and proximal interphalangeal joints (swan-neck deformity, boutonniere deformity, ulnar deviation). 

Volar plate injuries occur due to forced hyperextension of the proximal interphalangeal joint (PIPJ). There is avulsion of the insertion of the volar plate from the epiphysis at the base of the middle phalanx volarly, often only seen on the lateral or oblique radiographs (Fig. 19.17). Large fragments may require internal fixation. If they are unrecognised or progress to malunion, a swan neck deformity will... 

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