Acetabular Liner Extraction Assembly for Shell-Preserving Removal
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Solution Overview
Problem
Hard bearing liners, such as ceramic or metal, are difficult to remove from acetabular shells during revision procedures, often requiring destructive methods that can cause bone loss and prolonged healing times.
Innovation Solution
The development of tool assemblies that utilize impactors, faceplates, and extraction devices to securely engage the acetabular shell, apply force to separate the liner without disturbing the shell-bone interface, and minimize debris generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If destructive methods are used to remove hard bearing liners, then the liner can be removed from the acetabular shell, but bone loss occurs and healing time is prolonged
Solution Approach 1:
The impactor delivers controlled mechanical vibrations and shock waves through the acetabular shell to the liner, creating micro-fractures and loosening the liner-bone interface without requiring destructive removal methods. This vibrational mechanism allows liner extraction while preserving surrounding bone structure and avoiding bone loss.
Solution Approach 2:
The patent introduces an intermediary extraction device that engages with the liner through the shell without direct contact with bone. The device acts as a mediator to separate and extract the liner from the shell-bone assembly, preventing harmful direct manipulation of the bone-implant interface and avoiding bone loss during the removal process.
2Ease of operation
If destructive methods are used to remove hard bearing liners, then the liner can be removed from the acetabular shell, but healing time is prolonged
Solution Approach 1:
By using controlled vibrational forces to loosen and extract the liner, the procedure avoids extensive bone removal and structural damage. This preserves the integrity of the remaining bone and soft tissue, allowing for faster healing and reducing the overall healing time compared to destructive removal methods.
Solution Approach 2:
The extraction device enables selective removal of only the liner component while preserving and recovering the acetabular shell and surrounding bone structures. This selective extraction minimizes tissue damage and accelerates healing by maintaining the integrity of the host bone, thereby reducing healing time.
3Ease of operation
If traditional extraction devices are used, then the liner can be removed, but metal debris is generated
Solution Approach 1:
The vibrational extraction mechanism avoids high-impact destructive forces that generate metal debris. The controlled vibrations progressively loosen the liner through micro-fractures and interface separation, extracting the liner without creating significant metal particles or debris that would contaminate the surgical site.
Solution Approach 2:
The intermediary extraction device engages with the liner in a controlled manner that prevents uncontrolled fragmentation and debris generation. By providing a guided extraction path through the shell, the device prevents direct mechanical conflict between extraction tools and the liner that would otherwise generate metal debris.
4Ease of operation
If force is applied to separate the liner from the shell, then the liner can be removed, but the shell-bone interface may be disturbed
Solution Approach 1:
The impactor applies vibrational forces that propagate through the shell to the liner, creating separation at the liner-shell interface without requiring high axial forces on the shell. This vibrational separation mechanism preserves shell-bone interface integrity by avoiding excessive mechanical stress on the bone-implant connection.
Solution Approach 2:
The extraction device serves as an intermediary that applies force indirectly through the shell structure. By engaging the liner through the shell rather than directly manipulating the shell-bone interface, the device separates the liner while maintaining shell-bone integrity and avoiding disturbance to the bone-implant connection.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables efficient removal of liners while preserving the integrity of the shell-bone interface, reducing bone loss and healing time, and minimizing metal debris.
Implementation Method 1
an impactor configured to receive and transmit a force, the impactor comprising: a handle extending along a longitudinal axis and configured to be impacted on a proximal portion of the handle
Implementation Method 2
apply force to separate the liner without disturbing the shell-bone interface
Data Source
AI summary
A tool assembly for extracting a liner from a prosthesis comprising an impactor and a faceplate. The impactor can be configured to receive and transmit a force. The faceplate can be configured to deliver the force from the impactor to the prosthesis to separate the liner from a shell of the prosthesis.