Carpometacarpal joint dislocation

Mr Andrew Murphy and Dr Henry Knipe et al.

Carpometacarpal (CMC) joint dislocations are an uncommon dislocation of the hand.

There is a strong younger male predominance in the dominant hand.

The most common mechanisms of injury are punching followed by a fall.

The patient may present with ulnar deviation of the 5th digit if it is just the 5th CMC joint that is dislocated. They may present with a mass if the 3rd, 4th and 5th CMC joints are dislocated. Often the hand is so grossly swollen that these features may not be readily apparent.

Radiograph

Loss of the clear joint space and zigzag or M shape pattern between the carpals and metacarpals on the PA projection, although it may be normal, and the dislocation will only clearly be shown on oblique or lateral projections.

Associated injuries

The following injuries should be actively searched for or raise the suspicion of in CMC joint dislocations:

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Article information

rID: 23619
Synonyms or Alternate Spellings:
  • CMC dislocation
  • CMC joint dislocation
  • Carpometacarpal dislocation

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Cases and figures

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     Case 2: fracture-dislocation of the 4th and 5th CMC joints
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    Case 3: CT with hamate fracture
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    Case 4: dislocation of 4th and 5th CMC joints
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    Case 5
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    Case 6: 5th CMC joint
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    Case 7: dislocation of all CMC joints
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    Case 8: 5th CMC with base of metacarpal fracture
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