Comparison of three different internal fixation implants in treatment of femoral neck fracture-a finite element analysis.

BACKGROUND: Current surgical interventions for the femoral neck fracture are using either cannulated screws (CCS) or a single large screw at a fixed angle with a side-plate (i.e., a sliding hip screw, AKA dynamic hip screw, DHS). Despite these interventions, the need for reoperation remains high (10.0-48.8%) and largely unchanged over the past 30 years. Femoral neck fracture is associated with substantial morbidity, mortality, and costs.

METHODS: In this study, our group designed a plate that combines the strength of both CCS and sliding hip screw, through providing three dynamic screws at a fixed angle with a side-plate, namely the slide compression anatomic place-femoral neck (SCAP-FN). Finite element analyses (FEA) were carried out to compare the outcomes of the combination of our SCAP-FN plate with DHS+DS (derotational screw) and to those of using cannulated screws alone.

RESULTS: SCAP-FN produces more stable fixation with respect to the femur and the stress distributions, stress peaks, and rotational angles.

CONCLUSIONS: The FEA encouraged us that in the following biomechanical experiment, SCAP-FN may remain the strengths of both CCS and DHS+DS and show a better performance in resisting shearing and rotational forces, therefore achieving the best stability in terms of smallest displacement and rotational angle.