Watson and Ballet reviewed 4,000 wrist radiographs to map the sequence of degenerative wrist arthritis. They coined the term SLAC (scapholunate advanced collapse) for the most common pattern, affecting 57% of 210 cases. The paper asks whether recognizing this predictable pattern can guide surgical reconstruction — and proposes a staging system and operative strategy based on consistent sparing of the radiolunate joint.
Degenerative wrist arthritis is not random — it follows geometry. The elliptical radioscaphoid joint fails first; the spheroidal radiolunate joint is almost always preserved. Every modern wrist salvage procedure is built on this single observation from Watson's 1984 paper.
When you see a patient with wrist arthritis, stage it by the SLAC pattern: styloid-scaphoid tip (Stage I), full radioscaphoid (Stage II), then capitolunate (Stage III). Before offering any motion-preserving reconstruction, confirm the radiolunate joint is intact on plain films.
For symptomatic SLAC that has failed conservative management, scaphoid excision with four-corner fusion (capitate-lunate-hamate-triquetrum arthrodesis) routes all load through the preserved radiolunate joint. Watson's original series showed pain relief in 18 of 19 patients with no new radiographic degeneration at follow-up.
Do not reflexively offer proximal row carpectomy for advanced SLAC. Watson found the proximal capitate devoid of good cartilage in these cases. Making the capitate-on-radius articulation unreliable and the functional result compromised.
Watson and Ballet reviewed 4,000 wrist radiographs to map the sequence of degenerative wrist arthritis. They coined the term SLAC (scapholunate advanced collapse) for the most common pattern, affecting 57% of 210 cases. The paper asks whether recognizing this predictable pattern can guide surgical reconstruction — and proposes a staging system and operative strategy based on consistent sparing of the radiolunate joint.
Degenerative wrist arthritis is not random — it follows geometry. The elliptical radioscaphoid joint fails first; the spheroidal radiolunate joint is almost always preserved. Every modern wrist salvage procedure is built on this single observation from Watson's 1984 paper.
When you see a patient with wrist arthritis, stage it by the SLAC pattern: styloid-scaphoid tip (Stage I), full radioscaphoid (Stage II), then capitolunate (Stage III). Before offering any motion-preserving reconstruction, confirm the radiolunate joint is intact on plain films.
For symptomatic SLAC that has failed conservative management, scaphoid excision with four-corner fusion (capitate-lunate-hamate-triquetrum arthrodesis) routes all load through the preserved radiolunate joint. Watson's original series showed pain relief in 18 of 19 patients with no new radiographic degeneration at follow-up.
Do not reflexively offer proximal row carpectomy for advanced SLAC. Watson found the proximal capitate devoid of good cartilage in these cases. Making the capitate-on-radius articulation unreliable and the functional result compromised.