Acetabular Cup Peripheral Interlocks for Ceramic Implant Positioning
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Solution Overview
Problem
Existing acetabular cup insertion tools face difficulties in correctly positioning acetabular cups, particularly with ceramic acetabular cups, as they cannot be rotated axially or tilted, and existing tools for ceramic acetabular cups without damaging the structural integrity or articular surface, and suction force is insufficient for removal.
Innovation Solution
An acetabular cup with a smooth central bearing zone and peripheral bearing zone featuring insertion tool engagement holes, allowing for insertion and manipulation using a rod with radially operative interlocks that engage only in the peripheral zone, avoiding damage to the central bearing surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If engagement holes are made in ceramic acetabular cups to enable manipulation, then the cup can be rotated and positioned, but the structural integrity and articular surface are damaged
Solution Approach 1:
The bearing surface is segmented into two functional zones: a central smooth bearing zone for load-bearing and a peripheral engagement zone with holes for manipulation. This segmentation allows the cup to simultaneously achieve both structural integrity in the load-bearing area and manipulability in the peripheral area, resolving the contradiction between operation ease and strength.
Solution Approach 2:
Different regions of the acetabular cup are given different qualities: the central zone has a smooth, hole-free surface optimized for bearing loads, while the peripheral zone contains engagement holes optimized for manipulation. This local differentiation allows each region to perform its specific function optimally without compromising the other.
2Strength
If a rounded head insertion tool is used to avoid damage to the bearing surface, then the cup can be inserted, but the cup cannot be rotated or tilted for correct positioning
Solution Approach 1:
The bearing surface is segmented into a central smooth zone for insertion and a peripheral engagement zone for positioning. This allows the insertion tool to use the peripheral holes for rotation and tilting operations while the central smooth zone remains intact for bearing loads, resolving the contradiction between surface integrity and positioning capability.
Solution Approach 2:
The engagement holes are positioned at the periphery of the bearing surface, utilizing the peripheral dimension rather than the central bearing dimension. This spatial arrangement allows manipulation operations to occur at the edge of the cup without interfering with the central bearing zone, enabling rotation and positioning while preserving bearing surface integrity.
3Ease of operation
If suction force is used to hold the acetabular cup to the engagement tool, then the cup can be secured, but the suction force is insufficient for removal and twisting operations
Solution Approach 1:
Mechanical interlocks serve as an intermediary mechanism between the insertion tool and the acetabular cup. These interlocks physically engage with the cup through the peripheral holes, providing robust holding force that exceeds suction capabilities and enables both securing and manipulation operations including removal and twisting.
Solution Approach 2:
The suction-based holding mechanism is replaced with a mechanical interlocking system. The mechanical interlocks provide superior holding force and enable manipulation operations that suction cannot achieve, substituting a weaker pneumatic system with a stronger mechanical system.
Data Source
AI summary
An implant system has an acetabular cup with an interior bearing surface with a central bearing zone that is smooth and devoid of holes or indentations. The cup also has a peripheral bearing zone that contains insertion tool engagement holes. The engagement holes are only present in the peripheral zone and have specific shapes and dimensions. The system includes an insertion tool with retractable interlocks that fit within the engagement holes to position the cup during implantation. The central bearing zone bears the main forces during articulation, while the peripheral zone withstands minor forces. The location of the engagement holes has a negligible effect on the cup's performance. The cup can be made of ceramic and may have a coated exterior surface for osseointegration.