Monobloc Prosthetic Hip Head With Porous Coating
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Solution Overview
Problem
Dual mobility hip replacement constructs experience structural failures due to intra-prosthetic dislocation, material incompatibility leading to galvanic corrosion, and increased surgical time, with existing solutions failing to adequately address these issues.
Innovation Solution
A new prosthetic hip replacement assembly featuring a highly porous coated acetabular shell with a metal ball and stem made from compatible materials, coated with a thermoplastic layer to form a monobloc structure, reducing dislocation risk and eliminating the need for a separate liner, thus minimizing material differences and surgical complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dual mobility hip replacement construct uses a separate metal ball and plastic ball assembly, then dislocation risk is reduced, but intra-prosthetic dislocation occurs and surgical time increases
Solution Approach 1:
The patent merges the metal ball and plastic ball into a single monobloc structure where the metal ball is permanently embedded within the plastic ball during manufacturing. This eliminates the separate assembly of two balls that causes intra-prosthetic dislocation in dual mobility constructs, while maintaining the reduced dislocation risk benefit of dual mobility design.
Solution Approach 2:
The invention segments the acetabular component into a monobloc femoral head assembly (metal ball + plastic ball as one piece) that interfaces with the acetabular shell. This segmentation simplifies the surgical procedure by reducing the number of separate components to be assembled intraoperatively, thereby reducing surgical time and eliminating intra-prosthetic dislocation risks.
2Reliability
If different metal compositions are used for femoral stem and femoral ball, then material compatibility issues arise, but using same material reduces design flexibility
Solution Approach 1:
The patent applies local quality by using the same metal composition (cobalt-chromium) for both the femoral stem and the metal ball portion of the femoral head assembly to prevent galvanic corrosion at the interface. The plastic ball portion provides the necessary design flexibility and articulation properties, so the material flexibility is maintained in the plastic component while the metal components use compatible materials.
3Adaptability or versatility
If a separate liner is used in the acetabular shell, then assembly flexibility is improved, but the number of components and surgical complexity increases
Solution Approach 1:
The patent merges the femoral head assembly with the acetabular shell by directly implanting the monobloc assembly into the acetabular cavity without requiring a separate liner component. This reduces the total number of components from four (shell, liner, metal ball, plastic ball) to three (shell, monobloc femoral head assembly with integrated metal and plastic balls), simplifying surgery while maintaining assembly flexibility through the monobloc design.
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 significantly reduces the risk of dislocation, galvanic corrosion, and surgical time by creating a stable, fully articulating monobloc structure with compatible materials, enhancing the durability and efficiency of the hip replacement procedure.
Implementation Method 1
the thermoplastic coating is able to completely infiltrate the highly porous coating such that the thermoplastic and highly porous coatings can effectively interdigitate with each other so as to be integrally connected together
Data Source
AI summary
A prosthetic hip replacement assembly comprises a femoral stem, a femoral head adapted to be fixedly secured to the femoral stem, an acetabular shell adapted to be inserted into a surgically prepared acetabulum, and a liner fixedly secured within the acetabular shell and within which the femoral head is adapted to fully articulate. The femoral head comprises a ball, a highly porous coating, and a plastic coating formed upon the highly porous coating such that the plastic coating can infiltrate the pores of the highly porous coating whereby the femoral head comprises a monobloc structure comprising the ball, the highly porous coating, and the plastic coating. In an alternative embodiment, the liner can be eliminated.