APC II : Wheeless' Textbook of Orthopaedics

- Discussion:
- involves tearing of both anterior SI ligaments of floor of pelvis (sacrotuberous and sacrospinous);
- involves a widened anterior SI joint & injury to anterior ring (usually a symphysis diastasis) best seen on the Inlet view;
- may be bilateral or unilateral;
- this is a true open book injuries w/ splaying of anterior pelvis:
    - anterior constraint (anterior bony ring & sacrospinous, sacrotuberous, & anterior SI ligaments) are torn, leaving intact only the posterior SI ligaments (which serve as the binding of the book);

- Assessment of Stability:
- isolated division of symphysis pubis allows approx 2.5 cm of diastasis of symphysis pubis;
- further division of anterior sacroiliac, sacrospinous, & sacrotuberous ligaments causes further instability (APC II), but complete instability does not occur until all of sacroiliac ligaments are disrupted (Type III);

- Sequelae:
- this type of injury leaves the pelvis unstable to external rotation;
- may produce significant neural and arterial complications;

- Management:
- External Fixation:
   - consider anterior external frame;
       - pins should remain in place for approx 6-8 weeks;
    - Plate Fixation