Acetabular Cup With Segmented Recesses for Ceramic Bearing Fixation
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Solution Overview
Problem
Existing acetabular cup assemblies for artificial hip joints face issues where ceramic bearings are prone to breaking due to reduced contact area and overall strength is compromised, especially when using polyethylene bearings, as they require circular recesses that weaken the structure.
Innovation Solution
The acetabular cup assembly features a female taper on its inner wall with protrusion recesses and insertion recesses, along with a bearing having a male taper and protrusions that fit into these recesses, allowing for increased contact area with ceramic bearings and enhanced strength without a circular groove along the entire circumference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a circular recess is formed along the inner circumference of the acetabular cup to insert a polyethylene bearing, then the bearing can be firmly fixed, but the overall strength of the acetabular cup is decreased
Solution Approach 1:
The invention divides the fixation mechanism into two separate systems: protrusion recesses that communicate with the seating recess for radial fixation, and insertion recesses positioned above them for axial fixation. This segmentation allows bearing fixation without requiring a continuous circular recess, thereby maintaining cup strength while achieving reliable bearing retention.
Solution Approach 2:
The invention adds a vertical dimension to the fixation system by positioning insertion recesses above the protrusion recesses in the axial direction. This multi-dimensional approach enables fixation without compromising the circumferential integrity of the cup, as the recesses are localized rather than continuous.
2Ease of operation
If a circular recess is formed along the inner circumference of the acetabular cup to insert a ceramic bearing, then the bearing can be inserted, but the contact area between the bearing and acetabular cup is reduced, causing the ceramic bearing to be easily broken
Solution Approach 1:
The fixation structure is segmented into multiple discrete protrusion recesses distributed around the seating recess rather than a single continuous circular recess. This segmentation increases the total contact area between the bearing and acetabular cup while facilitating bearing insertion, thereby improving both ease of operation and bearing durability.
3Adaptability or versatility
If multiple recesses and locking portions are formed in the acetabular cup for bearing fixation, then bearing insertion is enabled, but the structural integrity and strength of the acetabular cup are compromised
Solution Approach 1:
The invention employs a nested structure where insertion protruding portions are inserted into insertion recesses that are positioned within or above the protrusion recesses. This nested arrangement achieves versatile bearing fixation capability while minimizing the structural disruption to the acetabular cup, as the recesses are contained within specific zones rather than compromising the overall structure.
Data Source
AI summary
An acetabular cup assembly for an artificial hip joint includes an acetabular cup including a seating recess, a female taper formed on an inner wall, protrusion recesses formed to communicate with the seating recess and insertion recesses each positioned inside a corresponding one of the protrusion recesses; and a bearing including a male taper on an outer circumference thereof, protrusions inserted into the protrusion recesses, and insertion protruding portions each formed on a corresponding one of the protrusions, the insertion protruding portions being inserted into the insertion recesses. A polyethylene bearing can be firmly fixed to the acetabular cup. When a ceramic bearing made is inserted into the acetabular cup, the area where the bearing adjoins the acetabular cup is increased, thereby preventing the ceramic bearing from being broken. Since no groove is formed along the entire circumference of the acetabular cup, the strength is increased.