Elastic Suspension Bone Plate Fixation
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Solution Overview
Problem
Existing osteosynthesis plates face challenges such as altered load distribution leading to bone resorption or fracture due to implant-induced stress risers, and overly stiff constructs that suppress necessary motion for fracture healing, delaying callus formation.
Innovation Solution
The use of elastic suspension of receiving holes in osteosynthesis plates allows for improved load distribution and controlled relative motion between bone fragments, achieved through the incorporation of elastic segments or spring elements that enable parallel translation and compression, reducing stress risers and promoting callus formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If locking plates with threaded receiving holes are used to provide stable fixation, then fixation stability is improved, but load distribution is altered causing bone resorption or stress risers
Solution Approach 1:
A cushion of elastic material is introduced as an intermediary element between the screw head and the bone plate. This elastic cushion mediates the load transfer, distributing stresses more evenly across the bone-plate interface and reducing both bone resorption and stress risers while maintaining fixation stability.
Solution Approach 2:
The stiffness parameter of the plate-bone interface is modified by introducing the elastic cushion material. This changes the mechanical properties of the construct from rigid to semi-flexible, allowing for more physiological load distribution that prevents bone resorption and stress concentration.
2Reliability
If locking plates with high stiffness are used to provide stable fixation, then fixation stability is improved, but relative displacement between bone fragments is suppressed delaying fracture healing
Solution Approach 1:
The bone plate construct is transformed from a static rigid structure to a dynamic semi-flexible system through the elastic cushion. This allows controlled relative displacement between bone fragments that stimulates callus formation and accelerates fracture healing while maintaining adequate fixation stability.
Solution Approach 2:
The stiffness parameter of the fixation construct is reduced by introducing the elastic cushion, enabling physiological micromotion at the fracture site. This controlled motion promotes fracture healing by callus formation while the elastic properties maintain sufficient stability for fixation.
3Adaptability or versatility
If non-locking screws with elastic material cushion are used to reduce construct stiffness, then relative motion is enabled, but plate compression onto bone surface prevents axial motion at fracture site
Solution Approach 1:
The fixation system is segmented into distinct functional zones: the elastic cushion allows rotation and lateral motion at the plate-bone interface, while the screw-bone interface maintains compression for axial stability. This segmentation enables multi-directional motion control appropriate for different healing requirements.
Solution Approach 2:
The system transitions from a uniformly rigid or uniformly flexible construct to a differentially flexible system. The elastic cushion provides dynamic compliance for rotational and lateral motions, while the compression mechanism maintains stability for axial loads, creating a dynamically adaptive fixation system.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances fracture healing by reducing stress concentrations and allowing necessary motion at the fracture site, thereby facilitating callus formation and improving bone fixation stability without compromising the screw-bone interface.
Implementation Method 1
the slot is filled with an elastomer material that provides an elastic suspension of the receiving hole relative to the bone plate
Implementation Method 2
elastomer material that provides an elastic suspension of the receiving hole relative to the bone plate, thereby promoting load distribution between screws
Data Source
AI summary
Embodiments provide methods, apparatuses, and systems for fixation of a fractured bone with a bone plate. In various embodiments, the systems and plates provide elastic suspension of the receiving holes relative to an osteosynthesis plate. This elastic suspension can promote load distribution between the screws that connect a bone segment to the plate, thereby reducing stress risers and load shielding effect. In addition, stress at the screw holes, and within the construct as a whole, is reduced by incorporation of these elastic elements in the plate. Additionally, in some embodiments where fracture healing by callus formation is desired, elastic suspension of the receiving holes relative to the osteosynthesis plate can enable small, controlled amounts of relative motion between bone fragments connected by the plate. This relative motion can promote fracture healing by callus formation.