Definition
Unstable injuries
Complete disruption of both the anterior and posterior ring
5 - 20% of pelvic fractures
Mechanism
Axial load
Motor vehicle accident
Fall from height
Pathology
Anterior ring
- pubic symphysis disruption
- fracture of the superior and inferior pubic ramus
- fracture acetabulum
Posterior ring
- fracture sacrum / SI joint / ilium
Initial Management
Femoral steinman pin + 20lb weight to reduce vertical displacement
Anterior external fixation to pelvis
Definitive Management
Lumbosacral fixation with SI screw - triangular osteosynthesis
Posterior stabilisation critical
Reduction
- closed
- open
Options
- sacro-iliac screws
- trans-sacral trans-iliac screws
- trans-iliac posterior tension band plating
- lumbosacral fixation
Anterior stabilisation
Pubic symphysis plates
Percutaneous ramus screws
Results
Griffin et al J Orthop Trauma 2006
- 62 patients with vertical shear fractures treated with SI screws
- increased failure rate in vertical sacral fractures compared sacro-iliac joint dislocation
- 20 vertical shear fractures
- 12 sacro-iliac dislocations and 8 vertical sacral fractures
- no failures in sacro-iliac dislocations
- failure in 4/8 vertical sacral fractures
- 3/4 failures of vertical sacral fracture fixed with single SI screw