Dual Mobility Hip Resurfacing With Polyethylene Liner Openings
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Solution Overview
Problem
Hip resurfacing implants face challenges with metal-on-metal articulation leading to adverse local tissue reactions and insufficient durability, limiting the implementation of dual mobility features.
Innovation Solution
A dual mobility hip resurfacing implant system with a cross-linked ultra-high-molecular-weight polyethylene liner featuring openings and grooves, allowing for swiveling and tilting movements, and differential radii to reduce wear and friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If metal on metal articulation is used in hip resurfacing, then durability is improved, but adverse local tissue reactions occur
Solution Approach 1:
The patent introduces a polyethylene liner as an intermediary material between the metal acetabular shell and the metal femoral head. This mediator eliminates direct metal-on-metal contact, preventing adverse local tissue reactions while maintaining the durability benefits of metal components. The liner acts as a biocompatible barrier that resolves the contradiction between durability and tissue compatibility.
Solution Approach 2:
The invention employs a composite construction combining metal acetabular shell with polyethylene liner, creating a hybrid articulation system. This composite approach leverages the strength and durability of metal while incorporating the biocompatibility and low wear characteristics of polyethylene, thereby resolving the contradiction between durability and adverse tissue reactions.
2Object-affected harmful factors
If polyethylene inserts are used in hip resurfacing, then adverse tissue reactions are reduced, but the inserts are too thin to have sufficient durability
Solution Approach 1:
The patent implements a nested structure where the polyethylene liner is positioned within the metal acetabular shell, and the metal femoral head is received within the liner. This nesting arrangement allows the thin polyethylene insert to be supported and protected by the surrounding metal structures, enabling sufficient durability despite the reduced thickness of the polyethylene material itself.
Solution Approach 2:
The polyethylene liner serves as an intermediary that is protected by the metal shell boundaries, allowing it to be thinner than traditional standalone polyethylene implants. The metal shell provides structural support and containment, enabling the use of thinner polyethylene while maintaining durability.
3Loss of substance
If dual mobility function is implemented, then component wear is reduced, but it has never been implemented in resurfacing due to space constraints
Solution Approach 1:
The patent realizes dual mobility through a nested three-component arrangement: the acetabular shell articulates with the polyethylene liner, and the femoral head articulates with the polyethylene liner. This nesting configuration enables independent movement at both articulation interfaces without requiring additional external space, as the components are contained within each other. The nested structure allows dual mobility functionality while respecting the space constraints of resurfacing anatomy.
4Quantity of substance
If minimal space is available in hip resurfacing, then bone preservation is improved, but articulation space is insufficient for durable inserts
Solution Approach 1:
The nested three-component structure (metal shell containing polyethylene liner containing metal femoral head) maximizes the use of available space by arranging components concentrically. This nesting approach preserves bone by avoiding complete femoral head removal while creating sufficient articulation space within the constrained resurfacing geometry through efficient spatial arrangement of the modular components.
Solution Approach 2:
The invention transitions from traditional two-component articulation to a three-component nested arrangement, adding a dimensional layer to the articulation system. This dimensional change allows the system to achieve durable articulation within minimal space by utilizing the radial dimension for component nesting rather than requiring additional axial or lateral space.
Data Source
Figure 1A~1B
Figure 2A~2C
Figure 3A~3B
AI summary
A system for bone resurfacing or total hip replacement, including an acetabular component (100, 400) having a first cavity (106), a dual mobility liner (110, 410) having a second cavity (116), the outer surface (112) of the liner being configured to be received within the first cavity (106) and articulable therein relative to the inner surface (104) of the acetabular component (100, 400) and a femoral component (120, 220, 420) having a head and a stem (128) extending from the head and being configured to be received within a femur, an outer surface of the head (122, 222, 422) being configured to be received within the second cavity (116). The dual mobility liner (110, 410) includes a plurality of openings (111) that extend from an outer surface (112) of the liner to an inner surface (114) of the liner, such that the plurality of openings (111) facilitate fluid communication between opposing sides of the liner (110, 410).