Internal Brace Plate Structure for Femoral Head Load Distribution
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Solution Overview
Problem
Traditional fracture fixation systems for femur fractures, particularly those involving intramedullary nails and lateral plates, often fail to provide sufficient support and stability, leading to non-unions, varus malalignments, and hardware failures due to high stress concentrations in the proximal screws targeting the femoral head.
Innovation Solution
A fracture fixation system comprising an elongated bone plate with a beam and support pin configuration, forming a figure-8 shape, which includes a peg and screw parallel to each other, and a support pin engaged with the bone plate and beam, reducing stress concentrations through a triangular structure that stabilizes the femoral head.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional fasteners are used to secure the bone plate to the femoral head, then the bone plate can be attached to the bone, but the fasteners flex and break under body weight load due to high stress concentrations
Solution Approach 1:
The fastener is divided into two separate components: a beam component and a support pin component. The beam component engages with the femoral head through a peg and screw configuration, while the support pin provides additional stabilization. This segmentation distributes the load across multiple elements, preventing any single fastener from bearing excessive stress that would cause flexing or breaking.
Solution Approach 2:
The support pin extends from the bone plate in a direction perpendicular to the plane of the bone plate, adding a third dimensional element to the fixation system. This vertical support element creates a triangular stabilization structure that distributes loads in multiple directions, reducing stress concentrations on the horizontal fasteners.
2Strength
If intramedullary nails are used for femur fractures, then the intramedullary canal can be stabilized, but proximal nail entry portals are not accessible or do not provide sufficient support for implantation
Solution Approach 1:
The bone plate serves as an intermediary fixation device that attaches to the lateral surface of the femur, providing stable fixation without requiring access to the intramedullary canal. The beam and support pin components work together to transfer loads from the bone plate into the femoral head and shaft, achieving intramedullary-like stabilization through an extramedullary approach.
3Stability of the object's composition
If lateral plates are placed to prevent varus malalignment, then varus prevention is achieved, but comminution of the lateral wall does not allow proper placement location with sufficient support
Solution Approach 1:
The beam component is configured with a curved geometry that conforms to the spherical shape of the femoral head. The peg and screw arrangement within the beam provides rotational stability and prevents varus malalignment while adapting to the curved bone surface, even in the presence of lateral wall comminution.
4Stability of the object's composition
If strong plates are contoured to the bone surface to minimize motion of fractured bone, then proper positioning is achieved, but the rigidity of the plate creates high stress concentrations in the fasteners
Solution Approach 1:
The fixation system is segmented into the bone plate, beam component, and support pin component. This segmentation allows the bone plate to provide rigid stabilization of the fracture while the beam and support pin components independently manage the loads transmitted to the femoral head, distributing stresses away from any single fastener connection point.
Data Source
AI summary
A fracture fixation system comprises an elongated bone plate including a proximal end and a distal end, the proximal end defining a proximal hole, and the distal end extending along a plate axis and defining a distal hole. The system comprises a beam including a peg extending along a peg axis and a screw extending along a screw axis, the beam having a first end and a second end, and a support pin including a first end and a second end. In an implanted configuration of the fracture fixation system, the peg axis is parallel to the screw axis such that the beam defines a figure-8 shape in a plane perpendicular to the peg and screw axes, the first end of the beam is engaged with the proximal hole of the bone plate, the first end of the support pin is engaged with the distal hole of the bone plate, and the second end of the support pin is engaged with the second end of the beam.