Dual Mobility Acetabular Cup Liner-Shell Fastening
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current dual mobility acetabular cup assemblies for artificial hip joints face issues with micromotion and fretting corrosion due to protruding parts that interfere with the femoral neck, leading to instability and wear, and require improved locking mechanisms for proper orientation and reduced wear.
Innovation Solution
A dual mobility acetabular cup assembly with a liner-shell fastening structure featuring penetration holes and protrusions for a stable fit, using tapered connections and plugs to prevent outward protrusions, ensuring secure alignment and reducing micromotion and wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional liner-shell coupling structure with protruding parts is used, then the liner can be secured in the shell, but the protruding parts interfere with the femoral neck causing micromotion and fretting corrosion
Solution Approach 1:
The invention removes the protruding rim structure from the liner that previously extended outward and interfered with the femoral neck. By extracting this harmful protruding element and replacing it with a flush or recessed coupling structure, the design eliminates the source of micromotion and fretting corrosion while preserving the locking function through alternative means such as tapered interfaces or internal retention features.
Solution Approach 2:
Instead of having the liner protrude outward to achieve retention, the invention inverts the approach by having the retention mechanism work inward or through a flush interface. The coupling structure is designed so that the liner sits level with or recessed from the shell outer surface, reversing the traditional protruding design and eliminating interference with surrounding anatomical structures.
2Ease of operation
If a simple insertion method is used, then assembly is easy, but proper orientation and stable fastening of the liner in the shell cannot be ensured
Solution Approach 1:
The invention incorporates asymmetric features such as non-circular cross-sections, keyed interfaces, or directional taper angles in the liner-shell coupling structure. These asymmetric elements provide inherent orientation guidance during assembly, ensuring the liner can only be inserted in the correct rotational position while maintaining ease of installation through a straightforward push-or-tap assembly process.
Solution Approach 2:
The design includes pre-formed alignment features, predetermined taper angles, or pre-positioned retention elements in the shell or liner that automatically guide proper orientation and seating during assembly. This preliminary structuring of alignment cues ensures correct positioning is achieved inherently during the simple insertion process without requiring additional alignment steps or complex tooling.
Data Source
AI summary
An implant for an artificial hip joint and, more specifically, a dual mobility acetabular cup assembly for an artificial hip joint is configured to have improved locking mechanism between a liner and a shell and improved resistance to micromotion and to guide the liner into the shell with proper orientation by providing stable liner-shell fastening structure to the acetabular cup assembly.