Intramedullary Nail Compression Mechanism for Controlled Dynamization

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Solution Overview

Problem

Conventional intramedullary nails lack controlled dynamization, leading to potential excess movement that can negate the benefits of axial compression for bone healing, prompting a need for improved designs that provide controlled dynamization and continuous compression.

Innovation Solution

Intramedullary nails with movable members and elastic compression members that allow for controlled axial movement and continuous compression, featuring mechanisms such as elastic projections, wedged split sleeves, and locking systems to manage dynamization during implantation and weight-bearing phases.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional intramedullary nails allow binary dynamization, then weight bearing can stimulate osseous growth, but excessive movement occurs that negates the benefits of dynamization

Engineering Contradiction:

Improvedynamization capabilityVSAvoidmovement control

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent changes the parameter of movement control from binary (conventional) to continuous and adjustable. The movable member design allows controlled axial movement between locked and unlocked positions, enabling precise regulation of dynamization parameters to optimize bone healing while preventing excessive movement.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent implements a dynamic system where the movable member can transition between fixed and mobile states. This dynamic capability allows the nail to adapt to different healing stages, providing stability when needed and controlled movement when beneficial for osseous growth stimulation.

Inventive Principle:

Principle #15Dynamics

2Strength

If intramedullary nails provide continuous compression to promote bone healing, then fracture site compression is maintained, but excessive movement during implantation occurs

Engineering Contradiction:

Improvecompression forceVSAvoidimplantation stability

Core Design Contradiction:

StrengthVSStability of the object's composition

Solution Approach 1:

The patent applies preliminary action by pre-configuring the movable member in a locked position during implantation. This preliminary locking state prevents unwanted movement during the implantation process, ensuring stability when continuous compression strength is not yet required.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system transitions from a static locked state during implantation to a dynamic unlocked state during healing. This dynamic behavior allows the nail to provide both implantation stability and subsequent continuous compression capability as needed at different stages.

Inventive Principle:

Principle #15Dynamics

3Reliability

If locking mechanisms are added to control dynamization, then movement is controlled, but device complexity increases

Engineering Contradiction:

Improvemovement controlVSAvoidlocking mechanism complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The movable member design incorporates self-locking and self-unlocking capabilities through its interaction with the lumen geometry and compression forces. The system uses the bone healing process itself to trigger/unlock the mechanism, reducing the need for complex external locking controls while maintaining reliable movement regulation.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent merges the locking mechanism functionality into the movable member structure itself, combining the compression application and movement control functions in a single integrated component. This integration reduces overall device complexity while maintaining reliable movement control during dynamization.

Inventive Principle:

Principle #5Merging (Combining)

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 enables controlled dynamization and continuous compression, facilitating faster bone healing without surgical intervention by mimicking natural bone movement, optimizing fracture stabilization and fusion.

Implementation Method 1

elastic compression members that allow for controlled axial movement and locking mechanisms, enabling continuous compression

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS12611235B2Intramedullary nail with automatic dynamization and continuous compression

Publication Date: 2026.04.28 GLW INC

AI summary

An intramedullary nail comprises an elongate body having a distal end, a proximal end, a distal portion, a proximal portion, an inner surface, and an outer surface, the distal portion disposed between the distal end and the proximal portion, the proximal portion disposed between the distal portion and the proximal end, the inner surface defining a first lumen extending through the distal portion and a second lumen extending through the proximal portion, the inner surface including a receiving surface; a first movable member disposed within the first lumen, the first movable member having a first movable member outer surface; a first peripheral projection disposed on the first movable member outer surface; a second movable member disposed within the second lumen, the second movable member having a second movable member outer surface; and a second peripheral projection disposed on the second movable member outer surface.