Bone Cement Extrusion Thread Design for Reduced Manual Force

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing bone cement dispensing devices face challenges in efficiently dispensing large quantities due to high friction and manual effort requirements, leading to difficulties in handling and potential air inclusion during mixing, which affects mechanical properties.

Innovation Solution

A device with a threaded rod and adapter unit, featuring a specific thread design with controlled outer surface area, pitch, and diameter, allowing for reduced friction and easier manual operation, enabling efficient extrusion of bone cement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conventional threaded rods with standard thread designs are used to extrude bone cement, then the mechanical strength is sufficient, but the friction is high and manual operation becomes difficult

Engineering Contradiction:

Improvemanual operation easeVSAvoidfriction force

Core Design Contradiction:

Ease of operationVSForce

Solution Approach 1:

The patent applies parameter changes by optimizing the thread geometry parameters - specifically reducing the outer surface area of one thread pitch to at most 370 mm², setting the pitch between 3-7 mm, and diameter between 10-20 mm. These parameter modifications reduce the friction surface area while maintaining mechanical strength, enabling easier manual operation for extruding large quantities of bone cement

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent applies local quality by creating a non-uniform thread design where the outer surface area of one thread pitch is specifically controlled to at most 370 mm². This localized optimization of the thread surface area reduces friction at the critical contact zone between the threaded rod and adapter unit, while other parts of the system maintain their standard design

Inventive Principle:

Principle #3Local quality

2Quantity of substance

If large quantities of bone cement are dispensed, then the fixation requirement is met, but the manual effort and friction increase significantly

Engineering Contradiction:

Improvebone cement quantityVSAvoidmanual effort

Core Design Contradiction:

Quantity of substanceVSEase of operation

Solution Approach 1:

The patent enables dispensing of large bone cement quantities (50-125 g or more) with reduced manual effort by changing the thread parameters - specifically the outer surface area of one thread pitch is limited to at most 370 mm², which reduces friction during the extrusion process. This allows surgeons to dispense the required large quantities without excessive manual effort

Inventive Principle:

Principle #35Parameter changes

3Device complexity

If bone cement is mixed manually in mixing cups, then the process is simple, but air bubbles are included which affect mechanical properties

Engineering Contradiction:

Improvemixing process simplicityVSAvoidair inclusion

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the manual mixing process with a mechanical mixing system where cement powder and monomer liquid are pre-packaged in separate compartments and automatically mixed together in a closed system. This substitution eliminates air bubble inclusion while maintaining process simplicity, as the mixing occurs automatically when the cartridge is attached to the adapter unit

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent creates a closed, controlled environment for mixing bone cement components, preventing air from entering the mixing process. The pre-packaged cartridges with separate compartments for powder and liquid are sealed, and the mixing occurs in a closed system, effectively creating an inert atmosphere that prevents air bubble formation

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

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 facilitates easy and cost-effective dispensing of large quantities of bone cement with reduced manual force, minimizing air inclusion and ensuring consistent mixing quality.

Implementation Method 1

a threaded rod (20) with an external thread (22), a handle (24) for rotating the threaded rod (20) and an adapter unit (26) for mechanical connection to a bone cement cartridge (12)

Methodology Applied

Scientific EffectMechanical Advantage: Mechanical Advantage

Implementation Method 2

the outer surface of one thread pitch of the external thread (22) is at most 370 mm2

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentEP4545027B1Device for extruding bone cement, use and system

Publication Date: 2025.10.01 HERAEUS MEDICAL GMBH

Figure 1
Figure 2
Figure 3~4

AI summary

The invention relates to a device for dispensing bone cement from a cartridge, a use of the device, and a system for dispensing bone cement. A device (10) for dispensing bone cement (15) from a cartridge (12) comprises a threaded rod (20) with an external thread (22), a handle (24) for rotating the threaded rod (20), and an adapter unit (26) for mechanically connecting it to a cartridge (12) for bone cement (15). The adapter unit (26) has a through-hole (27) with an internal thread (28) for the threaded rod (20). The outer surface area of a thread (66) of the external thread (22) is at most 370 mm². This allows for particularly easy dispensing of highly viscous bone cement.