Scapholunate advanced collapse

Last revised by Joshua Yap on 16 Apr 2023

Scapholunate advanced collapse (SLAC), commonly known as SLAC wrist, refers to a pattern of wrist malalignment that has been attributed to post-traumatic or spontaneous osteoarthritis of the wrist. It is a complication that can occur with undiagnosed or untreated scapholunate dissociation. It is essentially the same sequela of wrist injury causing scaphoid nonunion as seen in scaphoid nonunion advanced collapse (SNAC).

SLAC is most commonly a consequence of undiagnosed or untreated scapholunate ligament injury and rotatory subluxation of the scaphoid bone resulting in radioscaphoid malalignment, progressive chondromalacia, and osteoarthritis.

Its features, however, also have been observed in patients with idiopathic calcium pyrophosphate dihydrate (CPPD) crystal deposition disease.

The pattern is that of progressive osteoarthritis affecting initially the articulation between the radial styloid and the scaphoid. In later stages of the disease, osteoarthritis affects the whole radioscaphoid articulation, then the articulation between lunate and capitate. Finally, it may involve other intercarpal joints. In addition, there is scapholunate interval widening as well as proximal migration of the scaphoid and the capitate 3.

The Watson staging system is often used by hand surgeons 8

  • I: osteoarthritis of the articulation between the radial styloid and the scaphoid

  • II: osteoarthritis involving the whole radioscaphoid articulation

  • III: osteoarthritis of the radioscaphoid and capitolunate articulations

  • IV: osteoarthritis of the radiocarpal and intercarpal articulations +/- distal radioulnar joint (DRUJ)

Note that the radiolunate joint is almost preserved until the very last stages of the disease. It is also worth noting that the scaphoid fossa in the radius may be deep/preserved in cases of CPPD in contrast to post-traumatic SLAC wrist.

Key assessing parameters include 9:

Sagittal reformatted images from multidetector CT arthrographic data are particularly useful in demonstrating abnormal angulations of the scaphoid and lunate bones (increased scapholunate angle and dorsal or volar intercalated segment instability deformity), radioscaphoid incongruity, cartilage loss, and subchondral bone degenerative changes.

Surgical treatment for SLAC wrist includes four-corner arthrodesis, capitolunate arthrodesis, complete wrist arthrodesis, scaphoidectomy, proximal row carpectomy (PRC), denervation, and radial styloidectomy 2,5,6.

ADVERTISEMENT: Supporters see fewer/no ads

Cases and figures

  • Figure 1: SLAC from normal to stage 4
    Drag here to reorder.
  • Case 1: x-ray
    Drag here to reorder.
  • Case 2: MRI
    Drag here to reorder.
  • Case 3: CT
    Drag here to reorder.
  • Case 4
    Drag here to reorder.
  • Case 5
    Drag here to reorder.
  • Case 6
    Drag here to reorder.
  • Case 7: four-corner arthrodesis/scaphoidectomy
    Drag here to reorder.
  • Case 8
    Drag here to reorder.
  • Case 9: radioscaphoid arthritis
    Drag here to reorder.
  • Case 10: stage 1 with scaphoid nonunion and osteonecrosis
    Drag here to reorder.
  • Case 11
    Drag here to reorder.
  • Case 12: treated with proximal row carpectomy
    Drag here to reorder.
  • Updating… Please wait.

     Unable to process the form. Check for errors and try again.

     Thank you for updating your details.