Bone Plate with Sliding Elements for Elastic Osteosynthesis

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Solution Overview

Problem

Locked plating constructs for bone fractures are overly stiff, altering load distribution and suppressing interfragmentary motion, which can delay or prevent natural fracture healing and lead to implant breakage or screw loss.

Innovation Solution

An osteosynthesis plate with elastically suspended sliding elements that allow controlled displacement parallel to the longitudinal axis while maintaining stability in other directions, using a spring element and elastomeric material to facilitate motion and reduce stiffness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If locking plates are used to provide stable fixation, then fixation strength is improved, but interfragmentary motion is suppressed which delays fracture healing

Engineering Contradiction:
Improvefixation strengthVSAvoidfracture healing time
Core Design Contradiction:
StrengthVSDuration of action of moving object

Solution Approach 1:

The patent transforms the static locking plate into a dynamic system by introducing sliding elements that can move along the longitudinal axis within recesses. This dynamic capability allows the plate to permit controlled interfragmentary motion while maintaining fixation strength, thereby resolving the contradiction between stable fixation and fracture healing promotion

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the mechanical parameter of stiffness by allowing longitudinal displacement of sliding elements within recesses. This parameter modification enables the plate to provide appropriate motion for fracture healing while maintaining sufficient fixation strength, addressing the contradiction between these two requirements

Inventive Principle:
Principle #35Parameter changes

2Reliability

If locking plates with high stiffness are used, then fixation durability is improved, but load distribution is altered causing bone resorption or stress risers

Engineering Contradiction:
Improvefixation durabilityVSAvoidbone resorption and stress risers
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The sliding elements introduce dynamic adaptability to the fixation system, allowing it to adjust load distribution by permitting longitudinal motion. This dynamic behavior prevents excessive stress concentration and bone resorption while maintaining fixation durability, resolving the contradiction between reliability and harmful effects

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent modifies the stiffness parameter through the sliding mechanism, enabling the plate to distribute loads more physiologically by allowing controlled displacement. This parameter change reduces stress risers and bone resorption while preserving fixation durability, addressing the identified contradiction

Inventive Principle:
Principle #35Parameter changes

3Duration of action of moving object

If traditional compression plating is used, then interfragmentary motion is permitted for healing, but fixation stability is insufficient in weak osteoporotic bone

Engineering Contradiction:
Improvefracture healing processVSAvoidfixation stability
Core Design Contradiction:
Duration of action of moving objectVSStrength

Solution Approach 1:

The patent creates a dynamic fixation system where sliding elements can move longitudinally to permit healing motion while the locking mechanism provides stability against lateral displacement. This dynamic design addresses weak osteoporotic bone by providing angle-stable fixation while still allowing the interfragmentary motion needed for fracture healing

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent combines locking mechanisms (for stability in osteoporotic bone) with sliding elements (for permitted motion) within a single plate system. This composite approach integrates both rigid and flexible characteristics, resolving the contradiction between fixation stability and healing motion requirements

Inventive Principle:
Principle #40Composite materials

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 design promotes fracture healing by allowing necessary motion at the fracture site, reducing bone resorption, and enhancing load distribution, thereby improving construct strength and preventing implant-related complications.

Implementation Method 1

a spring element that suspends the sliding element and determines an amount of translation of the sliding element relative to the plate in response to a load acting in a longitudinal direction of the plate

Methodology Applied
Scientific EffectSpring: Spring

Implementation Method 2

The sliding element is suspended within a recess of the plate by an elastomeric material that comprises an elastomer lumen

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2811928B1Bone plate for elastic osteosynthesis
Publication Date: 2020.04.01 ZIMMER INC
  • EP2811928B1 patent drawingFigure 1
  • EP2811928B1 patent drawingFigure 2~4
  • EP2811928B1 patent drawingFigure 3

AI summary

Embodiments provide a method and device for plate osteosynthesis of a bone fracture that allows angle-stable fixation of the bone fracture, while permitting elastic axial motion at the fracture site in a controlled, symmetric manner to stimulate fracture healing. Embodiments pertain to a bone plate having an outer surface and a bone-facing surface. The bone plate incorporating internal sliding elements containing a threaded receiving hole for bone screws that have a correspondingly threaded screw head. The sliding elements undergo controlled displacement parallel to the longitudinal axis of the plate but are substantially constrained against displacement perpendicular to the longitudinal axis of the plate. The bone screws with threaded heads may be rigidly fixed to the threaded receiving holes in the sliding elements without compressing the bone plate onto the bone surface. Sliding elements are elastically suspended inside the bone plate and undergo dynamic motion.