Dynamic Bone Fixation Element via Additive Manufacturing

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Solution Overview

Problem

Existing dynamic bone fixation elements are costly and difficult to manufacture, limiting their availability and effectiveness in providing dynamic fixation for bone fractures, which requires micro-movement of bone fragments for proper healing.

Innovation Solution

A dynamic bone fixation element comprising a sleeve with a channel and a fixation member that allows for micro-movement, where the fixation member is movable relative to the sleeve along multiple directions, enabling micro-movement of bone fragments without the need for rigid welding, and can be manufactured using various techniques such as overmolding or 3D printing to reduce costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If dynamic locking screws with welded fixation members are used, then micro-movement capability is achieved, but manufacturing cost and complexity increase

Engineering Contradiction:
Improvemicro-movement capabilityVSAvoidmanufacturing cost and complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The fixation member and sleeve are merged into a single monolithic structure formed by additive manufacturing, eliminating the need for separate welding processes while maintaining the dynamic micro-movement capability between the fixation member and bone fragment

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The welding process is replaced with additive manufacturing technology, transitioning from traditional mechanical joining methods to a layer-by-layer deposition process that creates the fixation member with integrated features for micro-movement

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Stability of the object's composition

If rigid fixation is used, then bone fragments are stabilized, but stress concentration occurs

Engineering Contradiction:
Improvebone fragment stabilizationVSAvoidstress concentration
Core Design Contradiction:
Stability of the object's compositionVSStress or pressure

Solution Approach 1:

The fixation member is designed with dynamic characteristics that allow controlled micro-movement relative to the bone fragment, transitioning from static rigid fixation to dynamic fixation that adapts to physiological loading conditions and reduces stress concentration

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The mechanical properties of the fixation member are optimized through additive manufacturing parameters, including material composition, porosity, and structural geometry, to achieve appropriate flexibility and stress distribution characteristics

Inventive Principle:
Principle #35Parameter changes

3Productivity

If traditional manufacturing methods are used, then production is established, but manufacturing complexity and cost increase

Engineering Contradiction:
Improveproduction capabilityVSAvoidmanufacturing complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

Traditional multi-step manufacturing processes including welding, machining, and assembly are replaced with additive manufacturing, which builds the fixation member layer-by-layer directly from digital models, reducing manufacturing steps and complexity

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The additive manufacturing process provides universal capability to create various fixation member geometries and configurations from a single manufacturing system, eliminating the need for multiple specialized manufacturing processes

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3335655B1Dynamic bone fixation element
Publication Date: 2019.07.24 SYNTHES GMBH
  • EP3335655B1 patent drawingFigure 1
  • EP3335655B1 patent drawingFigure 2A~2B
  • EP3335655B1 patent drawingFigure 2C~2E

AI summary

A dynamic bone fixation element can include a sleeve elongate along a first direction and a fixation member. The sleeve can define a channel that extends from a proximal end through to a distal end along the first direction. The channel has a first cross-sectional dimension. The fixation member has a head, a shaft extending from the head and elongate along a second direction, and an abutment member extending from the shaft and integral with the shaft, wherein the shaft extends through the channel such that the sleeve is captured between the abutment member and the head. At least a portion of the shaft that is within the channel has a second cross-sectional dimension that is less than the first cross-sectional dimension such that the fixation member is moveable with respect to the sleeve along a direction that has a directional component transverse to the first direction.