Phalangeal dislocations are common, generally dislocate dorsally, are caused by hyperextension and axial compression, and may have associated volar plate damage. PIP volar dislocations can be irreducible secondary to rupture of the extensor tendon and herniation of the proximal phalanx through the extensor hood, requiring operative repair. MCP joint dorsal dislocations are often due to hyperextension. DIP dislocations are the rarest but can occur when an axial force is applied to the distal phalanx. Gross deformity is noted on examination, with the distal phalanx generally displaced dorsally.
Phalangeal Dislocation. This patient dislocated the long finger PIP joint during an altercation. The PIP joint is displaced dorsally with an obvious deformity. (Photo contributor: Cathleen M. Vossler, MD.)
Phalangeal Dislocation. Medial angulation of the ring finger suggests PIP dislocation. (Photo contributor: Daniel L. Savitt, MD.)
Volar Plate Injury. Subtle PIP swelling and ecchymosis of the long digit seen with a volar plate injury (A). Radiographs of volar plate injuries often reveal a small fragment on the volar surface of the PIP joint (B). (Photo contributor: Cathleen M. Vossler, MD.)
Management and Disposition
Digital nerve block for reduction and splinting is appropriate anesthesia for the PIP and DIP joints. Ulnar, median, or radial nerve blocks are necessary for the MCP joints. Reduction of dorsal dislocations is accomplished via joint hyperextension with concurrent application of horizontal traction followed by joint flexion. Flexion at the MCP joint will facilitate reduction of interphalangeal joints. Postreduction radiographs are necessary. After closed reduction of a dorsal dislocation, the DIP joint should be splinted in slight flexion and the PIP joint in at least 20 degrees of flexion for 3 to 5 weeks, depending on the degree of ligamentous damage. Hand specialist follow-up is recommended.
All joints should be tested for instability after reduction, using a digital nerve block to facilitate testing.
PIP joint volar dislocation can be unstable, requiring open reduction and internal fixation. Joint dislocations with volar plate entrapment may be impossible to reduce and require surgery.