Modular Femoral Augment Segmentation for Bone Defect Fixation
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Solution Overview
Problem
Current knee prostheses face challenges in achieving stable, long-term fixation in femurs with severe degeneration or trauma, particularly in areas with poor bone stock around the medullary canal, where traditional components are insufficient to compensate for bone loss.
Innovation Solution
A modular, multi-piece femoral augment system comprising a first augment with a proximal body and medial and lateral legs, and a second augment with a tapered outer surface, allowing for selective augmentation of metaphyseal and diaphyseal bone regions, using highly porous biomaterials like Trabecular Metal™ for secure bone ingrowth and integration with a femoral component.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional femoral components are used in femurs with severe bone loss, then the prosthesis can be implanted, but stable long-term fixation cannot be achieved due to insufficient bone stock
Solution Approach 1:
The femoral augment is divided into multiple segments including a proximal body and one or more legs (medial and lateral) that can be selectively assembled. This segmentation allows the implant to be customized to match different bone defect patterns and geometries, enabling stable fixation across varying bone stock conditions without requiring a completely different implant for each case.
Solution Approach 2:
The augment features locally varied geometry with a proximal body for metaphyseal support and distal legs for diaphyseal engagement. Each region is optimized for its specific function: the proximal body provides structural support in the metaphysis while the tapered legs provide stable fixation in the diaphysis, allowing the single implant design to address multiple bone quality scenarios.
2Manufacturing precision
If bone resection is performed to remove damaged bone stock, then the prosthesis can be positioned correctly, but the extent of bone loss increases making traditional components insufficient
Solution Approach 1:
The augment is designed to be extracted from the damaged bone environment and implanted into the bone defect cavity. The modular segments can be selectively removed or adjusted to precisely fill the void created by necessary bone resection, providing structural support without requiring excessive bone removal while achieving proper prosthesis positioning.
Solution Approach 2:
The femoral augment is nested within the bone defect cavity formed by resection of damaged bone. The proximal body nests in the metaphyseal region while the legs extend into the diaphyseal region, creating a nested configuration that restores structural integrity and enables proper prosthesis positioning without requiring removal of additional healthy bone.
3Device complexity
If a monolithic augment design is used, then the implant structure is simple, but it cannot provide selective augmentation of different bone regions (metaphyseal and diaphyseal)
Solution Approach 1:
The augment is segmented into a proximal body and separate legs that can be selectively assembled. This segmentation provides adaptability for selective augmentation of metaphyseal and diaphyseal regions while maintaining relatively simple individual component geometries that can be manufactured using standard processes.
Solution Approach 2:
The proximal body is designed with universal features that can accommodate different leg configurations and assembly options. This universality allows the same proximal body to work with various leg combinations to address different bone defect patterns, providing selective augmentation capability without requiring completely different implant designs for each scenario.
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
The modular system enables stable, long-term fixation of distal femoral implants by allowing selective augmentation and integration with the surrounding bone, minimizing healthy bone removal and promoting early bone ingrowth, thus enhancing the longevity and functionality of the prosthesis.
Implementation Method 1
using highly porous biomaterials like Trabecular Metal™ for secure bone ingrowth and integration with a femoral component
Data Source
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AI summary
A modular, multi-piece implant support structure system promotes stable, long-term fixation of a distal femoral implant (14) in femurs having damage and/or disease with varying degrees of severity. The modular support structure system facilitates selective augmentation of metaphyseal and/or diaphyseal bone surrounding the femoral medullary canal. In one exemplary embodiment, the system utilizes augment components (10, 12) which can be assembled into a large augment assembly, and can be used independently of one other.