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Simple Dislocations of the MP joint

- See: Complex Dislocations of the MP Joint

- Discussion:
    - two types of dorsal dislocation occur in MP joint: simple & complex;
    - simple dislocations: may be reduced by closed reduction,
    - complex dislocations: usually cannot be reduced primarily;
    - results from hyperextension injury;
    - most often occurs in index finger (and sometine little finger);
    - volar plate is torn from its proximal insertion into neck of metacarpal, remains attached to proximal phalanx;
            - in a complex dislocation, volar plate interposes into dislocated joint;
    - radial collateral ligament may tear resulting in ulnar deviation of the finger;

- Radiographs:
      - x-ray may show joint space widening (VP interposed);
      - look for chip fractures;

- Method of Reduction:
     - first hyperextended MCP joint to 90 deg, & then push base of proximal phalanx into flexion, maintaining contact at all times w/ head of metacarpal to prevent entrapment of volar plate in the joint;
     - wrist & IP joints are flexed to relax flexor tendons,  which facilitates joint reduction;

- Treatment:
     - if joint is stable following reduction, then consider buddy taping alone, allowing immediate active motion

A simplified technique for treating the complex dislocation of the index metacarpophalangeal joint.

Dorsal dislocation of the metacarpophalangeal joint of the index finger.

Injury to collateral ligament of the metacarpophalangeal joint of a finger.

Operation for collateral ligament ruptures of the metacarpophalangeal joints of the fingers.