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Avascular Necrosis of the Scaphoid

       



- See:
    - Scaphoid Reconstruction for Nonunion
    - Vascular Anatomy of Scaphoid:

- Discussion:
    - may be associated w/ longstanding nonunion of proximal pole fractures, especially when associated w/ previous surgery;
    - AVN of scaphoid is often difficult to diagnose radiographically and therefore it is usually necessary to assess vascularity of the 
           proximal pole at the time of surgery;
           - absence of punctate bleeding in the proximal fragment (after debridement) is the best indicator of AVN;
           - following debridement, punctate bleeding should be present from the surface of the scaphoid while the tourniquet remains elevated;

- Radiographic Findings:
    - plain radiographs tend to underestimate the presence of AVN (as compared to intraoperative bleeding or MRI);
    - proximal fragment may have:
          - ground-glass appearance or increased bone density;
          - loss of trabecular pattern;
          - cystic changes;
          - subchondral collapse and fragmentation;
    - radiographic classification:
          - stage 0: none;
          - stage 1: patchy areas of radiodensity of proximal pole;
          - stage 2: involvement of entire proximal pole;
          - stage 3: AVN w/ carpal collapse;

- MRI:
    - evolving role;

- Treatment:
    - Four Corner Fusion:



Avascular necrosis after scaphoid fracture: a correlation of magnetic resonance imaging and histology.

Late treatment of a dorsal transscaphoid, transtriquetral perilunate wrist dislocation with avascular changes of the lunate.

Surgical Treatment of Nonunion and Avascular Necrosis of the Proximal Part of the Scaphoid in Adolescents