Augmentation with silicone stabilizes proximal femur fractures: an in vitro biomechanical study

Prevention of hip fracture surgery in the elderly imposes great benefit for patient care as well as for society. The incidence of contra-lateral, second hip fractures after hip fracture surgery is as high as 20%. Augmentation of the contra-lateral proximal femur with silicone femoroplasty during hip fracture surgery of the ipsilateral hip could be a new preventive strategy. This study compared the degree of dislocation after a controlled induced fracture between treated and control cadaver femora.

Ten paired cadaver femora were randomly assigned for silicone femoroplasty and biomechanically tested for fracture load and dislocation against their native contra-lateral control. A load testing machine was used for fracture induction. All femurs were first fractured in a simulated fall configuration followed by dislocation in a "single leg stance" configuration. Dislocation was accessed using the AO-classification and measuring the Caput-Collum-Diaphysis angle.

Fracture loads were approximately 10% lower in the treated group (P=0.304). Forces needed to dislocate the proximal femur fractures did not significantly differ in both groups nor did the fracture type and AO-classification. All treated femurs showed complete reposition according to Caput-Collum-Diaphysis angle after dislocation versus only two of the controls (P<0.001).

From the results of this study we conclude silicone femoroplasty stabilizes the proximal femur by restoring hip geometry according to the Caput-Collum-Diaphysis angle after fracture. Future improvements in minimal invasive excavation and injection could make silicone femoroplasty an attractive alternative strategy in the prevention of hip fracture surgery in the growing population of low-demand, elderly patients.