Unstable / Displaced Scaphoid Fracture

- See: Radiographic Imaging

- Discussion:
    - unstable scaphoid fractures not only impact the potential for healing with non operative treatment, but they also impact on the position of 
           healing (and possible scaphoid non union or malunion);
    - indicators of instability:
           - trans-scaphoid perilunate dislocation;
           - displacement: greater than 1 mm of step off;
           - scapholunate dissociation:
                  - plastic deformation of the interosseous ligament may occur in upto 10 % of scaphoid frx;
                  - scapholunate angulation: greater than 60 deg of scapholunate angulation (on lateral view);
           - lunocapitate angulation:
                  - greater than 15 deg of lunocapitate angulation as observed on CT or x-ray;
                  - humpback scaphoid deformity is often associated w/ DISI deformity;
                  - DISI deformity is produced by a significant scaphoid humpback deformity;
                          - distal fragment continues to follow the palmarflexion tendency (of scaphoid), while proximal fragment tends to follow the lunate into extension;
                          - this results in dorsal intercalated segment instability, in which lunate is dorsiflexed abnormally forany given wrist position;
           - interscaphoid angulation:
                  - typically will have a dorsal scaphoid gap;
                  - w/ CT scanning: lateral interscaphoid angulation should not exceed 25 deg, and the posteranterior angulation should not exceed 35 deg;
                  - in the study by Amadio et al (1989), more than 45 deg of lateral intrascaphoid angulation, was
                          associated w/ an unsatisfactory outcome in 83% of patients

Scaphoid Malunion

Original Text by Clifford R. Wheeless, III, MD.

Last updated by Data Trace Staff on Friday, May 11, 2012 11:13 am