Bone Fixation Plate with Deformable Apertures and Curved Transitions
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Solution Overview
Problem
Existing bone fixation plates, particularly those made from thick surgical grade stainless steel, have been associated with increased tumor occurrences and weak stress zones due to sharp transitions between wide and narrow sections, which can lead to breakage and are not biocompatible.
Innovation Solution
A bone fixation plate with a head section and leg section featuring apertures that deform to form screw threads upon insertion, made from materials like stainless steel, titanium, or bioabsorbable polymers, allowing for adjustable screw placement and reduced material toxicity, with a design that minimizes stress concentrations and promotes biocompatibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If thick surgical grade stainless steel is used for fixation plates, then mechanical strength is improved, but tumor occurrence risk increases and biocompatibility worsens
Solution Approach 1:
The patent changes the material parameters by transitioning from thick surgical grade stainless steel to thin titanium alloy plates with reduced thickness (e.g., 2.4mm, 2.7mm, 3.5mm). This parameter change maintains sufficient mechanical strength through optimized geometry and material properties while reducing the harmful biological effects associated with thicker stainless steel implants, including tumor occurrence risk and foreign body reactions.
Solution Approach 2:
The patent employs titanium alloy materials that combine the benefits of high strength-to-weight ratio with superior biocompatibility. The titanium alloy composition (e.g., Ti-6Al-4V) provides a composite-like structure at the material level, offering both mechanical integrity and reduced biological toxicity compared to stainless steel, thereby resolving the contradiction between strength and biocompatibility.
2Ease of manufacture
If sharp transitions between wide and narrow sections are used in fixation plate design, then manufacturing simplicity is improved, but stress concentration increases leading to breakage
Solution Approach 1:
The patent applies curved transition zones between the wide head section and narrow leg section of the fixation plate. These gradual curved transitions eliminate sharp corners and abrupt geometry changes, distributing stress more evenly throughout the structure. The curved design maintains manufacturing feasibility while significantly reducing stress concentration points that would lead to plate breakage under load.
3Reliability
If pre-formed screw threads are used in apertures, then fixation security is improved, but screw insertion angle flexibility is reduced
Solution Approach 1:
The patent implements a dynamic aperture system where the internal threading structure can adapt to different screw insertion angles. The apertures are designed with flexible thread forms that can self-adjust during screw insertion, allowing screws to be inserted at varying angles while still achieving secure threaded fixation. This dynamic adaptation resolves the contradiction between fixation security and angular flexibility.
4Duration of action of stationary object
If permanent metal fixation plates are used, then long-term structural support is improved, but infection risk and x-ray visibility worsen
Solution Approach 1:
The patent changes the temporal parameters of the fixation plate by designing it as a temporary implant rather than a permanent one. The thin titanium alloy plate provides sufficient structural support during the critical bone healing period (typically 6-12 weeks), after which it can be removed or allowed to remain as a low-profile implant with minimal infection risk. This time-based parameter change optimizes the duration of action to match the bone healing timeline.
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
The solution provides a stronger, more biocompatible fixation plate that reduces the risk of tumor occurrence and breakage, while allowing for secure bone alignment and healing, with the ability to be absorbed by the body post-healing, thus minimizing infection risk and providing clear x-ray visibility of bone growth.
Implementation Method 1
the aperture is made from a material that deforms to form a screw thread within the aperture upon insertion of a threaded screw into the threadless aperture
Data Source
AI summary
A fixation plate comprising a head section for fixation to a first bone segment; a leg section extending from said head section for fixation to a second bone segment; wherein at least one of said head section and said leg section comprises at least one aperture configured to receive a screw for said fixation, and wherein said aperture is configured to receive said screw such that said screw can be inserted at varying angles.