Prosthetic Head Removal Tooling for Non-Impaction Stem Release
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for removing a prosthetic head from a locked engagement with a stem often involve impaction, which can cause adverse impacts on the patient.
Innovation Solution
A tooling system comprising an upper and lower tool with mating features and a holder, allowing for minimally invasive removal by engaging with the head and stem, and rotating the tools in opposite directions to unlock the head from the stem.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If impaction is used to break the engagement between the ball or head and the stem, then the head can be removed from locked position, but patient trauma increases
Solution Approach 1:
The patent introduces a specialized removal tool as an intermediary device between the surgeon's action and the locked head-stem engagement. This tool features a tapered surface that interfaces with the tapered engagement surface of the implant, allowing controlled mechanical action to be applied through an intermediate medium rather than direct impaction on the patient's anatomy. The tool acts as a mediator that translates rotational motion into controlled separation forces.
Solution Approach 2:
Instead of applying direct impaction forces to break the locked engagement, the patent inverts the approach by using a tapered tool surface that, when rotated, creates separating forces through the reverse mechanism. The tool's tapered geometry works in opposition to the locking taper, converting rotational input into axial separation that unlocks the engagement without harmful impact forces.
2Object-affected harmful factors
If a removal tool is inserted between the head and stem, then minimally invasive removal is enabled, but the tool structure becomes more complex
Solution Approach 1:
The removal tool is segmented into distinct functional zones: a tapered engagement surface for interfacing with the implant's locked connection, an extension portion for providing leverage and insertion depth, and a holder component for secure attachment to the implant. This segmentation allows each portion to perform its specific function efficiently while maintaining overall structural manageability despite the increased complexity.
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
A tooling system and method is disclosed for removing a head portion of a modular implant from a stem portion of the implant. The tooling system can include first and second tools configured to releasably mate together when the upper and lower tools are in an assembled position, and a holder configured to releasably secure the first and second tools in the assembled position. The first and second tools can be inserted between the head portion and an adaptor of the stem portion. When the first and second tools are rotated in opposite directions, the first tool can exert pressure on the head portion of the implant sufficient to release the head portion from locked engagement with the adaptor. The first and second tools can include mating features that disengage from each other as the tools are rotated in opposite directions.