Prosthetic Implant Sleeve Segmentation for Anatomical Load Distribution
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Solution Overview
Problem
Existing prosthetic implant sleeves do not have an anatomical profile, leading to incorrect joint load distribution, stress concentration, and excessive bone removal during surgical procedures.
Innovation Solution
A sleeve for a prosthetic implant with an external wall defined by a first and second portion, where the first portion has a first external surface obtained by rotating a first generatrix about a first longitudinal axis, and the second portion has a second external surface obtained by rotating a second generatrix about a second longitudinal axis, with the longitudinal axes being inclined by a given angle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the external wall has a cylindrical or conical profile, then the manufacturing is simple, but the joint load distribution is incorrect with stress concentration in contact areas
Solution Approach 1:
The sleeve external wall is divided into multiple zones with different geometries: a first portion with a first generatrix (e.g., cylindrical or conical) and a second portion with a second generatrix (e.g., tapered or anatomical profile). Each zone is optimized for its specific function - the first portion for ease of insertion and the second portion for anatomical conformity and proper load distribution, thereby resolving the contradiction between manufacturing simplicity and load distribution reliability.
Solution Approach 2:
The external wall profile is segmented into distinct portions along the longitudinal axis, with each portion having a different generatrix definition. This segmentation allows the sleeve to combine simple geometric forms for ease of manufacture with complex anatomical profiles for proper load distribution, effectively resolving the technical contradiction.
2Ease of manufacture
If the sleeve has a non-anatomical profile, then the manufacturing is easier, but excessive bone removal is required which weakens the bone
Solution Approach 1:
The sleeve profile is designed with local quality variations where the external wall transitions from simpler geometries to anatomically conforming shapes in specific zones. This allows the majority of the sleeve to be manufactured with simpler processes while only the critical proximal portion requires precise anatomical profiling, reducing overall manufacturing complexity while preventing bone weakening through proper load distribution.
3Stability of the object's composition
If the sleeve has a tapered shape to ensure support, then the proximal stability is improved, but the shape may require excessive bone removal
Solution Approach 1:
The sleeve is segmented into a first portion with a first generatrix that provides ease of insertion and a second portion with a second generatrix that provides the necessary tapered support. This segmentation allows the support function to be concentrated in the critical proximal region without requiring the entire sleeve to be tapered, thereby maintaining proximal stability while minimizing unnecessary bone removal.
4Device complexity
If the sleeve profile does not follow the femur profile, then the manufacturing is simpler, but incorrect joint load distribution occurs with stress concentration
Solution Approach 1:
The sleeve external wall is designed with local quality where the second portion has an anatomical profile that conforms to the femur shape in the critical load-bearing region, while the first portion maintains a simpler geometry. This localized anatomical conformity ensures proper joint load distribution and stress distribution without requiring the entire sleeve to be complex, thereby resolving the contradiction between device complexity and reliability.
Data Source
AI summary
Sleeve for a prosthetic implant implantable in bone, for example a femur, and related prosthetic assembly including at least a stem, intermediate neck component and sleeve.