Biomechanical Study Of Different Internal Fixation Methods For Acetabular Transverse Fractures

Objectives To compare the biomechanic stability of three different internal fixations for transvers acetabular fractures through the anterior approach.Methods Take the 9 specimens have complete pelvis, peel the soft tissue and Joint capsule attached to the pelvis and femoral shaft on, since the median sagittal plane saw the sacrum and the pubic symphysis, after trimming, pelvic specimens was 18.Transverse acetabular osteotomy line from the midpoint of the fracture model is greater sciatic notch after column acetabular roof, to uplift the midpoint of the anterior column iliopubic connection. Along this line with a saw cut off acetabular roof, thereby producing a transverse acetabular fracture models, The 18 transvers acetabular fracture models were randomly divided into three groups(n=6). The fractures were fixed with a6.5mm diameter lag screws in group A, with 12 holes reconstruction plate at each end of a fixed four screws in group B, and with 12 holes locking reconstruction plate at each end of a fixe four screws in group C. All specimens adjusted to the right position then put all the specimens were loaded on a mechanical testing machine, Loaded at a rate of 20 N/s,Until the internal fixation failure. Longitudinal displacements, loading of failed internal fixation and axial stiffness were measured by axial loading experiment sand compared between groups.All the data were analysis by the statistical software,they were statistically significant when the P<0.05.Results Longitudinal displacements of group A was longer than that of group B and C(P<0.05). The maximum load and axial stiffness of group A was smaller than those of group B and C(P<0.05). However, there were no significant differences in the longitudinal displacements, loading of failed internal fixation and axis stiffness between group B and C(P>0.05).Conclusions For the acetabular transverse fractures, locking reconstruction plate and reconstruction plate internal fixation can provide greater stability than simple lag screws.And the biomechanic stability of internal fixation with locking reconstruction plate is similar to reconstruction plate.