Programmable External Fixation Strut Adjustment With Sensor Data Link

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Solution Overview

Problem

Existing external fixation systems face challenges with manual strut length adjustments that are time-consuming, imprecise, and prone to human error, leading to potential complications in limb lengthening and deformity correction procedures.

Innovation Solution

A programmable tool with a data port for direct communication with the strut's internal sensor, enabling automated length adjustments and identification, reducing the need for manual measurement and identification steps.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual measurement and identification steps are used for strut adjustments, then the process is simple in terms of device complexity, but the adjustment precision and reliability deteriorate due to human error

Engineering Contradiction:
Improvestrut length adjustment precisionVSAvoidadjustment tool complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces manual mechanical measurement and identification processes with an automated programmable tool that uses electronic sensors and data ports to directly communicate with the strut's internal sensor system. This substitution eliminates human error in measurement while automating the adjustment process through programmed instructions.

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

Solution Approach 2:

The strut is equipped with an internal sensor and data port that enable it to automatically provide length information to the adjustment tool. The system performs self-measurement and self-identification, eliminating the need for external manual measurement devices and reducing the complexity of the adjustment process.

Inventive Principle:
Principle #25Self-service

2Productivity

If automated adjustment tools are implemented, then adjustment efficiency and precision improve, but the device complexity increases due to additional components

Engineering Contradiction:
Improvestrut adjustment efficiencyVSAvoidfixation system complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The programmable adjustment tool is designed to perform multiple functions: it measures strut length through the data port, identifies the specific strut being adjusted, executes programmed adjustment instructions, and provides feedback control. This multi-functionality consolidates what would otherwise require multiple separate devices into a single tool.

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

Solution Approach 2:

The patent combines the measurement function (internal sensor in strut), communication function (data port), and adjustment function (programmable tool) into an integrated system. The controller within the tool merges these functions to execute automated adjustment based on real-time sensor data.

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If internal sensors and data ports are integrated into the strut, then measurement accuracy improves, but the manufacturing complexity increases

Engineering Contradiction:
Improvestrut length measurement accuracyVSAvoidstrut manufacturing complexity
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The internal sensor and data port are nested within the existing strut structure. The sensor is positioned inside the strut body, and the data port is integrated into the existing mechanical interface, allowing these components to be incorporated without fundamentally redesigning the strut's external form or manufacturing process.

Inventive Principle:
Principle #7Nested doll (Nesting)

Data Source

PatentEP4491332B1Tool for external fixation strut adjustment
Publication Date: 2026.02.25 ORTHOFIX SRL
  • EP4491332B1 patent drawingFigure 1~3
  • EP4491332B1 patent drawingFigure 4
  • EP4491332B1 patent drawingFigure 5~6

AI summary

The present disclosure relates to a programmable tool (100) operable to adjust an external fixation strut (200) having a rotatable adjustment mechanism (201) for length adjustment, the programmable tool comprising: an output shaft (101); a motor (102) operable to rotate said output shaft (101); a first coupling portion (103) solidly attached to said output shaft (101) and adapted to releasably engage with a corresponding second coupling portion (203) of the rotatable adjustment mechanism (201), thus enabling torque transmission from the motor (102) to the rotatable adjustment mechanism (201); a controller (104) configured for driving said motor (102) according to a prescription comprising instructions for adjusting the external fixation strut (200); a first connecting portion (105) in electrical communication with said controller (104) and adapted to electrically connect with a second connecting portion (205) of the rotatable adjustment mechanism (201) when the first coupling portion (103) is engaged with the second coupling portion (203), thus enabling data transmission from the external fixation strut (200) to the controller (104).