[Biomechanical research on internal fixation methods of posterior pelvic ring fracture dislocation]

To investigate the biomechanical differences of three internal fixation approaches, namely improved Galveston (IG), reconstruction plate (RP), and iliosacral screw (LS) to the posterior pelvic ring fracture dislocation and provide experimental evidence for the clinical application of proper internal fixation method.

Six donated fresh adult cadaver pelvic specimens (age averaged 45 years old) were numbered randomly and their normal biomechanics were tested by the measure instrument (MTS855 Mini-Blonix). The displacement values of normal pelvis were measured under the vertical compression (800 N) and reverse direction compression (8 N x m). Then they were made into left Denis I pelvic fracture and fixed with the IG, RP, and LS, respectively, in different orders. Biomechanics test was conducted on the fixed pelvis from both the vertical and the reversed directions.

Concerning the direction of verticality and torsion, the order of fracture displacement from small to large was the normal pelvis, LS, IG and RP. There was no significant difference between LS and the normal pelvis (P > 0.05), and the differences between other tow groups were significant (P < 0.05).

The LS fixation can provide better stability for posterior pelvic ring fracture dislocation when compared with IG and RP.