Hip Endoprosthesis Acetabular Membrane Sealing
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Solution Overview
Problem
Existing hip joint endoprostheses with open bores for screw fixation risk bone abrasion and particle migration, leading to wear and tear, and osteolysis, as particles can enter the joint socket or migrate into the acetabulum, causing loosening and increased friction.
Innovation Solution
Introducing a membrane barrier into the bores of the joint socket to seal them when not in use, preventing bone particles from reaching the sliding surface or entering the acetabulum, using a conical membrane that is centered by the screw tip and seals upon screw insertion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bores are left open for screw fixation, then the acetabular cup can be securely anchored in the pelvic bone, but bone abrasion and particles can migrate through the bores into the acetabulum causing wear and osteolysis
Solution Approach 1:
A membrane is introduced as an intermediary element within the bores of the acetabular cup. This membrane acts as a barrier that prevents direct contact between the bone abrasion particles and the acetabulum while still allowing the bores to serve their fixation function. The membrane is positioned such that it blocks the bores from the articulation zone, preventing particle migration while maintaining the structural integrity and fixation capability of the acetabular cup.
2Object-affected harmful factors
If bores are sealed to prevent particle migration, then wear and osteolysis are reduced, but the ability to insert fixation screws is compromised
Solution Approach 1:
The membrane within the bores is designed to be dynamic rather than static. It can be displaced or repositioned during the surgical procedure to allow screw insertion, and then returned to its sealing position to prevent particle migration. The membrane's flexibility and ability to be manipulated during surgery enable it to serve dual purposes: facilitating screw insertion when needed and sealing the bore to prevent particle migration when not in use.
3Ease of operation
If continuous bores are used for fixation, then screw insertion is straightforward, but bone particles can freely migrate through the bores causing increased friction and wear
Solution Approach 1:
The membrane used in the bores is designed as a flexible thin film that can be easily inserted and manipulated. This flexible membrane effectively seals the bore to prevent bone particles from migrating through, thereby reducing wear and friction between the acetabulum and the joint ball. The flexibility of the membrane allows it to conform to the bore shape and maintain an effective seal while being easily handled during the surgical procedure.
Data Source
Figure 1
Figure 2A~4
AI summary
The artificial hip joint, assembled of a femur part and a ball joint to be accommodated in a complementary depression at the socket (2), is provided with bores (8) prepared in advance for the insertion of threaded bolts. In some cases no screws are required. The bores (8) are covered with conical membranes (10) at their upper ends (12), which can be easily penetrated by a screw if required, but keep the bores (8) closed and their inner spaces protected when no screws are inserted.