Acetabular Prosthesis with Variable Wall Thickness for Bone Anchorage
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Solution Overview
Problem
In redo operations and cases of degenerative or congenital diseases affecting the acetabulum, existing acetabular prostheses face challenges in achieving firm anchorage due to reduced bone areas and difficulty in identifying stable mechanical anchoring sites.
Innovation Solution
The acetabular prosthesis features a cup with a varying thickness wall, a protrusion with a through hole for a screw, and additional screws for engagement with the pelvic bone, allowing for independent positioning and stabilization, along with a threaded element for secure fixation, and optional ribs for enhanced rotational stability, using materials like titanium alloy or osteoinductive coatings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional fixation techniques (screws, cement, mechanical forcing) are used in redo operations or degenerative cases, then the prosthesis can be implanted, but firm anchorage cannot be achieved due to reduced bone areas and difficulty in identifying stable mechanical anchoring sites
Solution Approach 1:
The prosthesis features a cup with non-uniform wall thickness, with thicker regions strategically positioned to provide enhanced structural strength and stability in areas where bone support is compromised. This local quality variation allows the prosthesis to adapt to reduced bone areas while maintaining firm anchorage capability.
Solution Approach 2:
The fixation system is segmented into multiple independent screws that can be positioned at different locations and orientations. This segmentation allows surgeons to distribute fixation points across available bone areas, achieving reliable anchorage even when overall bone volume is reduced.
2Productivity
If the prosthesis design is simplified for easier implantation, then implantation speed increases, but the ability to achieve stable fixation in challenging conditions decreases
Solution Approach 1:
The prosthesis is pre-designed with an optimized wall thickness distribution pattern, eliminating the need for intraoperative customization or complex adjustments. This preliminary action ensures both rapid implantation and reliable fixation capability without compromising either productivity or stability.
3Reliability
If multiple screws are used for fixation, then anchorage stability improves, but the complexity of positioning and securing each screw independently increases
Solution Approach 1:
The cup wall thickness is locally optimized to provide enhanced structural support at specific regions where screws will be inserted. This local quality enhancement simplifies screw positioning by providing natural anatomical landmarks and reduces the complexity of achieving proper screw placement while maintaining high anchorage stability.
Data Source
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AI summary
The acetabular prosthesis (1) comprises a cup (2) designed to be inserted in a relative acetabulum and a first screw (6) for fixing the cup (2) designed to engage by screwing in a portion of pelvic bone, the cup (2) comprising a wall (3) with a substantially smooth outer face (3a), and a protrusion (4) extending outwards from the wall (3) and connected to the smooth face (3a).