Does surgically fixation of pubic fracture increase the stability of the operated posterior pelvis?

OBJECTIVES: This study aims to investigate whether surgical treatment of pubic rami fractures increases the stability of the posterior pelvis. PATIENTS AND METHODS: A finite element pelvic model with improved geometric and material characteristics was analyzed. By imitating a standing position, a type I Denis sacrum fracture and a unilateral pubis fracture, we measured the differences in tension and displacement. The posterior injury was treated with a direct plate synthesis or transsacral plate synthesis, while the pubis fracture was left without fixation or fixed with either a retrograde pubic screw or plate synthesis. RESULTS: The operative fixation of pubic rami fractures decreased the movement in the fracture gap not only at the site of the pubis fracture, but also at the site of the fixed sacrum fracture. The plate synthesis provided greater stability of the anterior fracture than the retrograde screw. The tensions in the implants were below the allowed values. CONCLUSION: We concluded that surgically fixation of pubic fracture increases the stability of the operated posterior pelvis.

Further development of our finite element pelvic model to compare fixation methods for pelvic fractures.

OBJECTIVES: In this study, we aimed to create a realistic model which is suitable for computerized simulation of any kind of fractures and provides reliable results. PATIENTS AND METHODS: We used a plastic pelvic model to construct advanced specimens. The data were retrieved from the computed tomography scans of a healthy pelvis. A geometrically exact model by the means of three-dimensional scanning of the plastic pelvis was obtained. The material properties of the bony parts based on the data retrieved from the computed tomography scans were modified. The pelvis was divided into distinct segments and the proportion of the cortical and cancellous bone substance in each segment were determined to make the material properties accurate. In the validation of the pelvic model, a type C pelvic injury was simulated and the fracture of the sacrum and the symphyseolysis were stabilized with plates. These data were compared with those of previously performed cadaver experiments. RESULTS: Based on the simulation performed on the new model, the shift values between the fragments of the broken sacrum approximated the reported values of our cadaver experiments and also arising strains remained in the tolerable interval. CONCLUSION: Our new finite element pelvic model represents the pelvis more accurately than the former one. As the validation of the model was successful, it is suitable for computerized simulation of any kind of fractures offering reliable results.