Definition
Scaphoid non union advanced collapse
Nonunion with resultant radiocarpal and midcarpal OA
Pathology
Scaphoid nonunion
- flexion deformity and abnormal joint mechanics
- radiocarpal osteoarthritis
- progresses from radial styloid / scaphoid fossa / midcarpal joint
- radiolunate joint preserved
Vender Classification
| Stage I | Stage II | Stage III |
|---|---|---|
|
Radial styloid and distal scaphoid fragment
|
+ Proximal scaphoid and capitate | + capitate-lunate joint |
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 |
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MRI
- comparison of xray and MRI for grading SNAC wrist
- MRI better at detecting carpal OA
Operative management
Options
Radial styloidectomy
Distal scaphoid excision
Scaphoid excision +/- arthroplasty
Proximal row carpectomy (PRC)
Scaphoidectomy + limited arthrodesis
Wrist arthrodesis
Results
Four corner fusion v proximal row carpectomy (PRC)
Hones et al J Hand Surg Am 2024
- systematic review of 3000 SNAC wrists
- four corner fusion v PRC
- better ROM with proximal row carpectomy
- lower subsequent arthrodesis with proximal row carpectomy: 5% v 11%
Ahmadi et al J Plast Recons 2022
- systematic review of four corner fusion v PRC
- comparable outcomes
- PRC simpler procedure and no hardware complications
Williams et al J Wrist Surg 2018
- 123 PRC v four corner fusion with 8 year follow up
- no difference in outcomes
- PRC: reoperation rate 16%, conversion to fusion 15%
- Four corner fusion: reoperation rate 20%, conversion to fusion 34% (nonunions, hardware issues)
Distal scaphoid excision
Indication
Stage I
Results
- systematic review of distal scaphoid excision for SNAC
- 70 patients
- 69% complete pain relief
- 88% satisfaction
Proximal row carpectomy
Concept
Remove scaphoid / lunate / triquetrum
Allow capitate to articulate with lunate fossa of the radius
Indication
Stage II: preserved capitate
Stage III: consider adding capitate resurfacing
Technique
Vumedi dorsal approach PRC video
Results
- systematic review of PRC +/- capitate resurfacing
- 1700 PRC v 80 PRC + capitate resurfacing
- at one year better outcomes with addition of capitate resurfacing
Scaphoidectomy & Limited arthrodesis
Indication
Stage II / III: Preserved radio-lunate joint
Concept scaphoidectomy + limited arthrodesis
| 4 corner fusion | 4 corner / bicolumn | 3 corner fusion | 2 corner fusion |
|---|---|---|---|
|
Capitate - lunate Triquetrum-hamate-capitate
|
Capitate-lunate Triquetrum-hamate |
Capitate - lunate Capitate - hamate +/- triquetrum excision |
Capitate - lunate |
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Scaphoidectomy and four corner fusion
Bain et al J Hand Surg Am 2010
- 10 year follow up of scaphoidectomy and four corner fusion in 31 patients
- no change in grip strength
- flexion reduced 22%
- mean satisfaction 80%
- 2 patients underwent arthrodesis
Two versus four corner fusion
Schriever et al J Hand Surg Eur 2024
- RCT of lunate-capitate fusion versus four corner fusion
- 64 patients with SNAC / SLAC wrist
- at 12 months no difference in outcomes
Hundepool et al J Hand Surg Am 2025
- systematic review of 80 articles and 2000 patients
- two versus three versus four corner fusion
- similar outcomes
- two corner fusion better ROM
- nonunion two corner fusion: 10%
- nonunion four corner fusion: 7%
Fixation options
K wires
Headless compression screws
Dorsal locking plates
Staples
4 corner fusion techniques
4 corner: capitate / lunate screw + triquetrum / hamate / capitate screw
Bi-column: capitate / lunate screw + triquetrum / hamate screw
Vumedi scaphoidectomy and four corner fusion with screws
Arthrex scaphoidectomy and four corner fusion with staples
Acumed four corner fusion plate surgical technique PDF
2 corner fusion techniques / capito-lunate fusion
Vumedi scaphoidectomy and capito-lunate fusion video
Wrist arthrodesis
Indications
End stage disease
Manual worker
www.boneschool.com/wrist-arthrodesis
