Hip Prosthesis Extraction Instrument with Soft Coupling Insert
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Solution Overview
Problem
Existing medical instruments for extracting hip joint endoprostheses risk damaging the coupling cone during removal, leading to a compromised secure connection with the neck piece or joint ball due to scratches and raised portions.
Innovation Solution
A medical instrument with a coupling body comprising a coupling base body and a coupling insert, where the coupling insert is softer than the coupling cone, minimizing damage by only allowing contact with the insert and using different materials for the base body and insert to ensure stability and prevent damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a medical instrument with a coupling body is used to extract the prosthesis stem, then the prosthesis stem can be removed from the femur bone, but the coupling cone may be damaged causing scratches and raised portions that prevent secure self-locking connection
Solution Approach 1:
The coupling body is divided into two separate components: a coupling base body and a coupling insert. The coupling insert is the part that directly contacts the coupling cone, while the coupling base body provides structural support. This segmentation allows the coupling insert to be made of a softer material that protects the coupling cone, while the base body remains sufficiently stable for extraction forces.
Solution Approach 2:
Different parts of the coupling body have different material properties optimized for their specific functions. The coupling insert has a softer, more compliant material quality suitable for protecting the coupling cone surface, while the coupling base body has a harder, more rigid material quality suitable for withstanding extraction forces. This local differentiation of material properties resolves the contradiction between protection and structural stability.
2Stability of the object's composition
If the coupling body is made of a single stable material, then structural stability is maintained, but the coupling cone is at risk of damage from hard surfaces
Solution Approach 1:
The coupling body is segmented into a coupling base body and a coupling insert that can be separated. This allows each component to be made from materials optimized for its specific function: the base body for structural stability and the insert for protective contact with the coupling cone.
Solution Approach 2:
The coupling body uses a composite construction with two different materials: a harder, more stable material for the coupling base body and a softer, more protective material for the coupling insert. This composite approach allows the system to simultaneously achieve structural stability and protection of the coupling cone from damage.
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 prevents damage to the coupling cone, ensuring a secure extraction of the prosthesis stem while maintaining a stable connection, allowing for the use of various prosthesis stems with minimal instrumentation and facilitating minimally invasive surgeries.
Implementation Method 1
the coupling insert is softer than the coupling cone, minimizing damage by only allowing contact with the insert
Data Source
AI summary
The invention relates to a hip joint endoprosthesis system, comprising a medical instrument for extracting an implanted prosthesis stem of a hip joint endoprosthesis from a femur bone of a patient, which medical instrument has a coupling body with a coupling recess for accommodating a coupling cone protruding from the prosthesis stem, wherein the coupling body comprises a coupling base body and a coupling insert which is accommodated in a coupling insert receptacle of the coupling base body and defines the coupling recess.