Femoral Hip Stem Alignment Device for ISO 7206-4 Test Orientation

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Solution Overview

Problem

Current methods for aligning femoral hip shaft implant components for load tests are prone to significant deviations, leading to non-reproducible and non-comparable test results due to reliance on visual judgment, which can result in incorrect alignment and repeated testing.

Innovation Solution

An alignment device with a head clamp that can be tilted and locked vertically, featuring an axis rail with a pointing edge and adjustable shaft clamps to precisely determine and align the shaft axis according to ISO 7206-4:2010 standards, eliminating the need for visual alignment and ensuring accurate positioning of points K and L.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If manual visual alignment method is used to align the shaft axis, then the alignment process is simple and quick, but the alignment precision is low leading to significant deviations

Engineering Contradiction:
Improvealignment precisionVSAvoidalignment device complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces an alignment device as an intermediary tool between the manual visual alignment and the implant component. This device includes a positioning element that contacts the implant at a specific point and a alignment indicator that provides a reference for correct orientation, thereby mediating the alignment process to achieve higher precision without requiring complex automated systems

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the purely manual visual alignment method with a mechanical alignment device that uses physical contact points and geometric constraints to determine the shaft axis. This mechanical substitution eliminates reliance on operator visual judgment while maintaining operational simplicity

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

2Reliability

If manual visual alignment is performed, then the operation is easy to perform, but the reliability of test results is low due to non-reproducible alignment

Engineering Contradiction:
Improvetest result reliabilityVSAvoidalignment operation ease
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent changes the alignment parameter from subjective visual judgment to objective geometric parameters defined by the alignment device. The device establishes fixed spatial relationships between contact points and alignment indicators, transforming the alignment process into a parameter-based procedure that ensures reproducibility while remaining easy to execute

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The alignment device performs preliminary action by pre-establishing the correct geometric relationships and reference positions before the actual test begins. The device is designed with predetermined dimensions and contact points that automatically define the shaft axis orientation, eliminating the need for repeated adjustments and verification during testing

Inventive Principle:
Principle #10Preliminary action

3Productivity

If visual judgment is used for shaft axis determination, then no additional equipment is needed, but alignment errors occur leading to repeated testing

Engineering Contradiction:
Improvetesting efficiencyVSAvoidshaft axis determination precision
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The alignment device serves as an intermediary tool that bridges the gap between simple visual alignment and precise measurement. It provides tangible reference elements that are easy to observe and use, yet deliver accurate shaft axis determination, thereby improving testing efficiency without introducing complex equipment

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3261585B1Orientation device for orienting femoral hip-stem implant components for test purposes
Publication Date: 2019.03.13 WALDEMAR LINK GMBH & CO KG
  • EP3261585B1 patent drawingFigure 1
  • EP3261585B1 patent drawingFigure 2
  • EP3261585B1 patent drawingFigure 3

AI summary

The aim of the invention is to provide an option for excluding errors when measuring by eye and for a more exact orientation of hip-stem implant components that are to be oriented for a stress test according to ISO Standard 7206-4:2010. To achieve this aim, an orientation device for orienting femoral hip-stem implant components (H) is disclosed, said device comprising a head clamping element (8), which can be vertically displaced on a strut (4), for clamping a ball head (Ko) of a hip-stem implant component (H), the head clamping element (8) being tiltable about two horizontal axes (9, 10) running perpendicularly to one another and being lockable in various tilted positions in relation to the horizontal axes (9, 10). The orientation device (1) is characterised in that it also has an axis bar (15) with an indicator edge (18) running in a straight line in the longitudinal direction of the axis bar (15), two stem clamps (17), which can be displaced in the longitudinal direction, for clamping a stem section (S) of the hip-stem implant component (H) and a stop (16), oriented transversely to the longitudinal direction, for a stem tip (T) that lies opposite the ball head (Ko) of the hip-stem implant component (H). The stem clamps (17) are designed such that each clamp secures the stem section (S) centrally in the section against which the stem clamps (17) rest.