Scaphoidpseudarthrose

Scaphoid non-union is one of the complications of scaphoid fracture because of the unique anatomy of the scaphoid and its vascular supply.

Epidemiology

Scaphoid fractures have one of the highest rates non-union of all fractures at ~10% (range 5-15%) .

Pathology

Scaphoid non-union occurs most commonly through the middle or proximal thirds .

Classification

Six grades of non-union have been described by Slade and Dodds :

  • grade 1: delayed presentation - 4-8 weeks
  • grade 2: fibrous non-union - minimal fracture line; no cyst or sclerosis
  • grade 3: minimal sclerosis - <1 mm bone resorption with minimal sclerosis
  • grade 4: cyst formation and sclerosis - <5 mm bone resorption with cyst formation; normal scaphoid alignment
  • grade 5: cyst formation and sclerosis - 5-10 mm bone resorption with cyst formation; normal scaphoid alignment
  • grade 6: separate bone fragments with profound bone resorption; fragment motion and scaphoid deformity common

The following subtypes can also be applied:

  • a: proximal pole non-union 
  • b: avascular necrosis (AVN)
  • c: ligamentous injury
  • d: deformity

Complications