Orthopedic Prosthesis Mold Assembly for Accurate Interim Implant Sizing
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Solution Overview
Problem
Existing methods for creating orthopedic prostheses, such as temporary knee joint implants, face issues with overfilling, spillage, deformation, and the need for multiple sizes, leading to increased surgical time and soft tissue damage.
Innovation Solution
The use of a dual-housing orthopedic prosthesis mold system with varying hardness levels and alignment features, including shell elements and connection elements, to prevent separation and deformation, and provide adjustable sizing options.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional negative molds are used to create temporary implants, then the surgeon can form custom implants, but the process increases surgical time due to preparation and formation time
Solution Approach 1:
The mold system is prepared and assembled before the surgical procedure begins. The housing, shell elements, and connection elements are pre-configured to enable rapid implant formation during surgery, eliminating the need for time-consuming preparation steps during the actual surgical procedure.
2Loss of time
If block or spacer method is used to create temporary implants, then the implant can be quickly placed, but the knee must be completely immobilized in an extended position leading to soft tissue damage
Solution Approach 1:
The mold system enables creation of temporary implants with specific local characteristics - including articulating surfaces and controlled range of motion capabilities - rather than uniform block spacers. This allows different portions of the implant to have different functional properties, permitting limited knee movement while maintaining structural support.
3Productivity
If pre-made disposable molds are used, then the molding process can be standardized, but overfilling and spillage occur leading to wasted materials and messy work area
Solution Approach 1:
The system includes vent ports that provide feedback during the injection process, allowing excess material to escape and signaling when the mold cavity is properly filled. This prevents overfilling and material waste while maintaining standardized molding efficiency.
4Device complexity
If pre-made disposable molds are used, then the process can be simplified, but the molds require cutting to remove from the implant which is cumbersome and can damage the prosthesis
Solution Approach 1:
The mold system is divided into separable components - the housing and shell elements can be detached from each other, and the connection elements provide controlled attachment that can be easily released. This segmentation allows the prosthesis to be removed intact without cumbersome cutting operations.
5Manufacturing precision
If molds are filled with curable material, then the prosthesis can be formed, but the pressure inside the mold can cause the mold and prosthesis to deform
Solution Approach 1:
The mold system uses composite construction with a housing made from one material and shell elements made from a different material with complementary properties. This composite structure distributes and manages the pressure from curable material injection, preventing deformation while maintaining prosthesis shape accuracy.
Data Source
AI summary
An orthopedic prosthesis mold, comprising a first housing including a first cavity therein shaped to form a portion of an orthopedic prosthesis; a second housing coupled to the first housing, the second housing including a second cavity therein shaped to form a portion of an orthopedic prosthesis, wherein the first and second housings are constructed from a material having a first hardness; a first shell element configured to receive at least a portion of the first housing therein; a second shell element configured to receive at least a portion of the first housing therein, wherein the first and second shell elements are constructed from a material having a second hardness greater than the first hardness; and a connection element releasably engageable to the first and second shell elements to prevent separation of the first shell element from the second shell element.