Intramedullary Nail Lockable Fastener Mechanism

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Solution Overview

Problem

Current nailing systems for femur fractures and reconstructions lack versatility and effectiveness in securely engaging and disengaging bone fasteners, particularly in varying angles and positions, which complicates surgical procedures and stability post-surgery.

Innovation Solution

An orthopedic device featuring an intramedullary implant with a cannulated movable member that telescopically moves within a longitudinal bore, defining guiding bores for bone fasteners at variable angles, and a securing device that can lock or unlock fasteners, allowing for secure engagement and disengagement of multiple fasteners at different angles and positions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a traditional nailing system is used for femur fracture fixation, then the surgical procedure is relatively simple, but the device lacks versatility in engaging bone fasteners at varying angles and positions

Engineering Contradiction:
Improveversatility in engaging bone fastenersVSAvoiddevice complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The cannulated movable member is received within the longitudinal bore of the intramedullary implant, creating a nested configuration where one component fits inside another. This allows the securing device to operate within the existing implant structure, providing additional functionality without requiring a completely separate external device, thus enhancing versatility while controlling complexity.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The movable member can telescopically move between engaged and disengaged positions relative to the intramedullary implant. This dynamic capability allows the device to adapt to different surgical needs - engaging when fastener security is required and disengaging when adjustment or removal is needed - thereby providing versatility through motion rather than through multiple static components.

Inventive Principle:
Principle #15Dynamics

2Stability of the object's composition

If multiple bone fasteners are secured at varying angles and positions, then fracture fixation stability is improved, but the ease of operation during surgery is reduced

Engineering Contradiction:
Improvefracture fixation stabilityVSAvoidease of operation
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The securing device with the movable member serves multiple functions: it can engage and secure multiple bone fasteners at different angles and positions, and it can be moved between engaged and disengaged states. This multi-functionality allows a single device to handle various fastening configurations, improving fracture fixation stability while maintaining relative ease of operation through standardized procedures.

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

Solution Approach 2:

The movable member acts as an intermediary between the intramedullary implant and the bone fasteners. It provides a standardized interface that can accommodate fasteners at varying angles and positions, simplifying the surgical operation by providing a consistent mechanism for securing different fasteners rather than requiring different techniques for each configuration.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If a securing device with movable member is used to engage and disengage fasteners, then fastener security is improved, but the device complexity increases

Engineering Contradiction:
Improvefastener securityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The movable member is nested within the intramedullary implant's longitudinal bore, utilizing the existing structural space. This nested configuration provides a secure engagement mechanism without adding external complexity, as the securing device operates within the boundaries of the existing implant rather than requiring additional external components.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The telescopic movement capability of the movable member provides a simple mechanical means to transition between secured and unsecured states. This dynamic feature enhances fastener security by allowing reliable engagement when needed while maintaining device simplicity through a single degree of freedom motion rather than complex locking mechanisms.

Inventive Principle:
Principle #15Dynamics

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

Enhances the stability and versatility of bone fixation by enabling secure engagement and disengagement of fasteners, facilitating more effective fracture fixation and reconstruction procedures, while allowing for active compression of fractures.

Implementation Method 1

a resilient portion couplable to the movable member

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

The locking member can have an externally threaded portion threadably engageable to a threaded portion of the longitudinal bore

Methodology Applied
Scientific EffectScrew mechanism: Screw

Data Source

PatentEP2341854B1Lockable intramedullary fixation device
Publication Date: 2013.09.25 BIOMET MFG LLC
  • EP2341854B1 patent drawingFigure 1
  • EP2341854B1 patent drawingFigure 1A
  • EP2341854B1 patent drawingFigure 2

AI summary

An orthopedic device can include an intramedullary nail (102) with a longitudinal bore, first and second bone fasteners (140) with sleeves (144) and a cannulated movable member (260) received within the longitudinal bore. The movable member defines first (164) and second (166) guiding bores for receiving respectively the first and second fasteners. Each of the first and second guiding bores includes a pair of opposing deformable elongated strips (800). Each pair of strips can engage the sleeve of a corresponding bone fastener.