Dorsal intercalated segment instability

Dorsal intercalated segment instability (DISI) is a form of instability involving the wrist. It occurs mainly after the disruption of the scapholunate ligament and is more often encountered than volar intercalated segment instability (VISI).

  • radial or dorsal wrist pain, maximal on radiation deviation and wrist extension
  • weakness and/or instability
  • clicking wrist
  • positive Watson test: during ulnar to radial deviation, pressure applied to the volar aspect of the scaphoid elicits an audible and/or palpable clunk (due to dorsal subluxation of the scaphoid with respect to the radius)

Fixed DISI deformity only occurs after combined injury of scapholunate ligament and other stabilizers of the scaphoid, namely radioscaphocapitate and scaphocapitate ligaments.

On an AP view, the normal trapezoidal configuration of the scaphoid may be lost and it may appear triangular.

On the lateral radiograph with the wrist in a neutral position, DISI typically demonstrates dorsal tilt of the lunate with both of the following present:

On sagittal CT, the same findings as on plain radiograph are seen.

On sagittal MRI 9, the same findings as on plain radiograph are seen. However, bone contusion, scaphoid avascular necrosis and scapholunate ligament injury are evaluated with more precision.

Wrist pathology

Article information

rID: 9709
Tag: wrist
Synonyms or Alternate Spellings:
  • DISI
  • DISI deformity
  • Dorsiflexed intercalated segment instability
  • Dorsal intercalated segmental instability

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Cases and figures

  • Figure 1
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  • Case 1
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  • Figure 2
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  • Case 2: following scaphoid fracture
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  • Figure 3
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  • Case 3
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  • Case 4
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  • Case 5
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  • Case 6
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  • Case 7: treated with proximal row carpectomy
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