Artificial Joint Cup Insert Pivoting Mechanism
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional artificial joints face a trade-off between dislocation suppression and range of motion, where increasing the height of the high wall to suppress dislocation reduces the range of motion and vice versa, and the neck portion often contacts the high wall, impairing the joint's degree of freedom.
Innovation Solution
An artificial joint design featuring a cup and insert with a coupling portion that allows the neck portion to pivot and push the insert into the cup, utilizing a recess and projection fitting structure to regulate movement and prevent dislocation, while maintaining a wide range of motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the height of the high wall is increased to suppress dislocation, then the dislocation suppression effect is improved, but the range of motion of the joint decreases
Solution Approach 1:
The cup is divided into a fixed outer cup and a movable inner insert, allowing the insert to pivot independently within the cup. This segmentation enables the high wall structure to provide dislocation suppression while the pivoting insert maintains joint range of motion by accommodating neck portion movement without requiring a fixed high wall that would restrict motion.
Solution Approach 2:
The insert is designed to pivot dynamically about a pivotal axis within the cup, transitioning from a static high wall structure to a dynamic system. The insert can rotate to accommodate the neck portion's movement during joint flexion and extension, providing dislocation suppression adaptively without limiting the joint's range of motion.
2Reliability
If the high wall is made larger to prevent dislocation, then the dislocation suppression effect is improved, but the neck portion comes into contact with the high wall more frequently, reducing joint freedom
Solution Approach 1:
The insert pivots about a pivotal axis to dynamically adjust its position, allowing the high wall structure to provide dislocation suppression only when needed (when dislocation risk is present) while permitting normal joint motion during flexion and extension. This dynamic adaptation prevents unnecessary contact between the neck portion and high wall.
Solution Approach 2:
The pivoting insert acts as an intermediary between the fixed cup and the moving femoral component. It mediates the interaction by providing dislocation suppression through its high wall structure while simultaneously accommodating the neck portion's movement through pivoting, thus preventing direct contact between the neck portion and the fixed cup's high wall.
3Reliability
If the cup margin is deepened to encase the bone head portion, then the dislocation suppression effect is improved, but the neck portion and cup margin are easily in contact, decreasing range of motion
Solution Approach 1:
The cup is segmented into a fixed outer cup and a movable inner insert, allowing the insert to pivot independently. This segmentation enables the insert margin to provide dislocation suppression while the pivoting motion prevents frequent contact between the neck portion and the margin, maintaining joint range of motion.
Solution Approach 2:
The insert margin is designed to pivot dynamically with the insert about the pivotal axis, allowing it to follow the neck portion's movement during joint flexion and extension. This dynamic motion prevents the neck portion from frequently contacting the margin while maintaining the encasement effect for dislocation suppression.
Data Source
AI summary
The artificial joint of the present invention is provided with a cup having a first housing part that opens on one first-direction side, an insert that is housed in the first housing part and has a second housing part that opens on one first-direction side, a movable member having a spherical head part rotatably housed in the second housing part and a neck part extending from the head part, and a connecting part that connects the insert to the cup pivotably around a pivotal axis extending in a second direction; the neck part contacting an edge part of the insert by pivoting around the pivotal axis; the insert pivoting around the pivotal axis; and part of the opposite side of the side pushed in by the neck part across the pivotal axis protruding from the cup to one first-direction side.