In-Situ Knee Spacer Forming Device with Open-Sided Punch
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for producing knee spacers during revision surgeries are cumbersome, often result in air inclusions that damage the articulation surfaces, and are difficult to detach without damaging the spacer, requiring extensive time and resources, and are not adaptable to specific antibiotic needs.
Innovation Solution
A device with a punch surface featuring a negative image of the articulation surface, open on the side to prevent air inclusion, and adjustable separators to set cement thickness, along with an ejection facility for easy detachment, made from inexpensive and easily disinfectable materials like thermoplastics, allowing for in-situ production of smooth and stable knee spacers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional casting molds are used to produce knee spacers, then the spacer can be formed in-situ, but air inclusions are trapped that damage the articulation surfaces
Solution Approach 1:
The invention extracts the harmful air inclusions from the system by providing open sides on the punch surface that allow air and excess cement to escape during the forming process, preventing air entrapment that would otherwise damage the articulation surface
Solution Approach 2:
Instead of using a closed mold that traps air, the invention inverts the approach by using an open-sided punch surface that actively allows air to escape, transforming the problem of air entrapment into a controlled ejection process
2Manufacturing precision
If enclosing molds are used to form the spacer, then the shape is well-defined, but the molds are difficult to detach without damaging the spacer
Solution Approach 1:
The invention segments the mold structure by providing open sides on the punch surface, dividing the enclosing space into open regions that allow easy access for detachment while maintaining shape definition through the negative image of the articulation surface
Solution Approach 2:
The invention extracts the ejection function by incorporating ejection facilities directly into the punch surface, allowing the mold to self-eject the formed spacer without requiring complex external detachment mechanisms
3Manufacturing precision
If extensive reworking and separate anchoring steps are performed, then the spacer can be properly installed, but the surgery time and resource consumption increase
Solution Approach 1:
The invention merges multiple operations into a single in-situ forming step, combining spacer formation, shape definition, and ejection into one process that eliminates separate reworking and anchoring steps, thereby reducing surgery time while maintaining installation quality
Solution Approach 2:
The invention performs preliminary shaping of the spacer in-situ during the cement application process itself, forming the articulation surface directly in its final position before the cement cures, eliminating the need for subsequent reworking operations
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 rapid, air-free formation of smooth articulation surfaces, reduces the risk of spacer damage during detachment, and simplifies the production process, making it more efficient and universally applicable while ensuring the spacer's mobility and patient comfort.
Implementation Method 1
pressing a device according to the invention onto the bone cement
Data Source
AI summary
Devices and methods in-situ produce articular spacers from a bone cement. The devices and methods have a punch surface for forming an articulation surface of a spacer in the bone cement, whereby the bone cement is arranged on a bone surface for fixation of the spacer, whereby the punch surface has a negative image of the articulation surface to be produced, and the surface forming the negative image is open on the side, at least in part, such that the bone cement can be pushed towards the side, away from the articulation surface to be formed. Moreover, the method for producing an articular spacer on a bone may have one or more of the following steps: A) Applying a bone cement to a prepared bone; B) Pressing said device onto the bone cement; and C) Detaching the device from the cured bone cement.