Modular Tibial Cone Augments for Secure Revision Knee Fixation
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Solution Overview
Problem
In revision knee surgeries, existing orthopaedic surgical instruments and methods struggle to effectively address bone loss and defects in the tibia and femur, particularly when using cone augments that are not mechanically locked to the revision prosthesis, requiring additional bone cement for securement.
Innovation Solution
A method involving the use of tibial and femoral cone augments implanted into surgically-prepared cavities in the tibia and femur, guided by stem trial components and surgical broaches, with the option of bone cement for securement, and the use of modular tibial cone augments with a central and side lobe components for customizable fit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If cone augments are used that are not mechanically locked to the revision prosthesis, then the surgical procedure can be simplified and component selection is more flexible, but additional bone cement is required for securement which increases the risk of cement-related complications
Solution Approach 1:
The patent introduces a stem component as an intermediary element that mechanically connects the cone augment to the revision prosthesis. The stem is inserted through the cone augment and secured to the prosthesis, providing direct mechanical lockation while allowing the cone augment to remain separately implantable. This mediator resolves the contradiction by enabling both surgical simplicity and reliable securement.
2Manufacturing precision
If modular tibial cone augments with customizable lobe components are used, then the fit to various bone defects can be optimized, but the device complexity and number of components increase
Solution Approach 1:
The tibial cone augment is divided into a central lobe component and optional side lobe components that can be selectively attached. The central lobe provides the basic conical fit, while side lobes can be added to accommodate specific bone defects. This segmentation allows customization of the fit precision without requiring a completely different design for each defect scenario, managing complexity through modular addition rather than complete redesign.
Solution Approach 2:
The side lobe components are designed to be selectively attached only where needed to address specific bone defects. Rather than providing a uniformly complex structure, the local quality principle allows the augment to remain simple in areas where standard conical fit suffices, while adding complexity only in specific locations where bone loss requires additional support.
3Strength
If excessive bone cement is used to secure the cone augment and prosthesis, then securement strength is improved, but the risk of cement-related complications such as embolism and loosening increases
Solution Approach 1:
The patent replaces reliance on bone cement with a mechanical connection system. The stem component features a tapered distal end that locks into a corresponding recess in the prosthesis, creating a direct mechanical interlock. This mechanical substitution eliminates or reduces the need for bone cement, providing securement strength through mechanical means rather than chemical bonding, thereby reducing cement-related complications.
Data Source
AI summary
An orthopaedic joint replacement system is shown and described. The system includes a number of prosthetic components configured to be implanted into a patient's knee. The system also includes a number of surgical instruments configured for use in preparing the bones of the patient's knee to receive the implants. A number of methods for using the surgical instruments to prepare the bones is also disclosed.