JMIR Publications

ABSTRACT

Intertrochanteric hip fractures rank in the top ten of all impairments worldwide in terms of loss in disability-adjusted years for people older than 60 years-old. The type of surgery is usually carried out with Sliding Hip Screw (SHS) devices or chephalomedullary nails (CMN). Cut-out of the hip screw is considered the most frequent mechanical failure for all implants with an estimating incidence ranged from 2% to 16.5%; this entails both enhancing our understanding of the prognostic factors of cut-out and improving all aspects of intertrochanteric fracture treatment. DRIFT’s main objective is to provide intertrochanteric fracture treatment expertise, requirements and specifications, clinical relevance and validation, to improve treatment outcomes by developing a universal algorithm for designing patient- and fracture-oriented treatment. The hypothesis to be tested is that a more valgus reduction angle and implants of higher angles will lead to a more favorable biomechanical environment for fracture healing, that is, higher compressive loads at the fracture site with lower shear loads at the hip screw femoral head interface. Also, to design and fabricate a new implant with enhanced biomechanical and technical characteristics; an integrated design and optimization platform based on CAD design tools and topology optimization modules will be developed. To test this hypothesis a biomechanical study comprised of experimental loading of synthetic femora (Sawbones INC, Malmoe, Sweden) and Finite Element Analysis (FEA) will be conducted. Detailed finite element analysis of existing implants (DHS & CMN) implemented in different clinical cases under walking conditions will be performed to derive the stress and strain fields developed at the implant-bone system and identify critical scenarios which could lead to failure of therapy. These models would be validated against instrumented mechanical tests using strain gauges and Digital Image Correlation (DIC) process. From this step, the geometrical drawbacks of existing implants will be fully recognized and the geometrical characteristics will be correlated with critical failure scenarios. The last step would be the numerical design, CAD design (using FEA codes and design packages) and optimization of the new proposed implant with regard to improved biomechanical surgical technique and enhanced mechanical performance that will reduce the possibility for critical failure scenarios.