Anterior stabilization in the pubic symphysis separation: a mechanical testing.

Four types of commonly used instruments, 1) external fixation, 2) tension wiring, 3) tension band wiring, and 4) single superior plating, for anterior stabilization of the diastasis pubic symphysis were tested for their mechanical properties under single load to failure in cadaveric pelvis by a universal testing machine. Three directions of loading, transverse tension, vertical tension and saggital compression, were used to test each type of instrumentation. Five specimens of each fixation were used for each direction of testing. The strongest instrumentation was single superior plating. Early mobilization can be advocated in the patient after fixation with this instrument. External fixation could resist transverse and saggital compression load at an acceptable level but not the vertical load. Tension band wiring could better resist vertical load than the other directions. Tensions wiring was the weakest instrumentation and early ambulation should be avoided.