Bone Fixation Device with Deformable Arm and Threaded Aperture Lip
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Solution Overview
Problem
Existing bone fixation devices require a perfect match between the device and bone profile, leading to displacement issues, especially in elderly patients or those with low bone density, and are difficult to deform and remove without damaging the bone.
Innovation Solution
A plastically deformable bone fixation device with apertures defined by a combination of threaded and smooth portions, including a step change for abutment, allowing for secure engagement with screws without exact profile matching, and deformable connecting arms for easy shaping and twisting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the bone fixation device is designed with a rigid structure requiring perfect profile matching, then the initial fixation stability is improved, but the device becomes difficult to deform and may cause displacement when bone density is low
Solution Approach 1:
The bone fixation device incorporates a deformable connecting arm that transitions from a rigid state during fixation to a flexible state during deformation. The arm can be bent into different configurations (straight, angled, curved) to match various bone profiles, and then locked in place to provide stable fixation. This dynamic adaptability resolves the contradiction between initial stability and deformability.
2Reliability
If the bone fixation device requires perfect profile matching with the bone, then the fixation reliability is improved, but the surgical procedure complexity increases and the device becomes difficult to remove
Solution Approach 1:
The bone fixation device is segmented into a rigid fixation body and a separate deformable connecting arm. The connecting arm can be independently deformed into various profiles to match the bone, while the fixation body remains simple and standardized. This segmentation reduces overall device complexity while maintaining fixation reliability through the deformable arm's profile adaptation.
3Ease of operation
If the bone fixation device uses a smooth aperture design, then the screw insertion ease is improved, but the locking reliability deteriorates due to lack of engagement features
Solution Approach 1:
The aperture in the fixation body features localized threading in specific regions while maintaining smooth walls in other areas. The threaded portions provide secure screw engagement and locking reliability, while the smooth portions facilitate easy screw insertion and removal. This local differentiation of aperture quality resolves the contradiction between insertion ease and locking reliability.
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 device can be securely locked to the bone without matching the bone's profile, simplifying surgical procedures and reducing the risk of displacement, while allowing for easy deformation and removal without damaging the bone.
Implementation Method 1
Each aperture comprises a threaded portion and a bowl shaped smooth portion. In use a screw is threaded into engagement with the screw receiving aperture.
Implementation Method 2
the head being adapted to abut the lip with an abutment force, the abutment force being directed substantially radially outwards so producing a tight fit
Implementation Method 3
a plastically deformable bone fixation body having at least one screw receiving aperture extending therethrough
Data Source
AI summary
A bone fixation device includes a plastically deformable bone fixation body having a screw receiving aperture extending therethrough. The shape of the aperture is defined by a side wall having a first threaded portion, a second smooth walled portion extending from the first threaded portion, and a third smooth walled portion extending from the second portion. The aperture has a step change in cross section between the second and third portions defining a lip. The second and third portions are connected by a lip face extending substantially normal to the aperture length with the edge of the lip face defining the lip. The device further includes at least one bone fixation screw having a shaft and a head. The shaft engages with the first threaded portion of the aperture and the head abuts the lip with an abutment force being directed substantially radially outwards so producing a tight fit.