Cruciate-Retaining Tibial Prosthesis Bridge Design
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Solution Overview
Problem
Cruciate-retaining tibial prosthetics in knee arthroplasty procedures face challenges due to the weakening of the tibial eminence attachment site during installation, as significant native tissue removal is required, leading to potential failure of the tibial eminence.
Innovation Solution
A tibial prosthetic system with an elevated bridge configuration that reduces bone resection and increases the intercondylar passage width, distributing compressive forces across a larger area, thereby preserving the natural attachment strength of the tibial eminence and enhancing structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional tibial prosthetic component is installed to replace the resected portion of the tibia, then the joint can function with artificial prosthetic components, but the surrounding native tissue is significantly removed which weakens the attachment strength of the tibial eminence
Solution Approach 1:
The tibial prosthetic component is divided into separate medial and lateral base portions that are positioned on either side of the tibial eminence, with the bridge structure spanning between them. This segmentation allows the prosthetic to provide support without requiring removal of the central tibial eminence and its surrounding native tissue, thereby preserving attachment strength while still replacing the necessary bone portions.
Solution Approach 2:
The bridge structure extends superiorly from the base portions to form an elevated configuration that spans the intercondylar passage. This dimensional elevation allows the bridge to provide structural support and distribute forces without interfering with the cruciate ligaments passing through the intercondylar region, while simultaneously preserving the tibial eminence attachment site below.
2Reliability
If the intercondylar notch width is increased to preserve more native bone around the tibial eminence, then attachment strength is improved, but the structural integrity of the connecting structure between medial and lateral base portions decreases
Solution Approach 1:
The bridge structure extends superiorly to elevate the connecting structure between medial and lateral base portions, creating a three-dimensional configuration. This elevation allows the bridge to span a wider intercondylar passage while maintaining structural integrity through its extended length and optimized cross-sectional geometry, without requiring compromise of either attachment strength or connecting structure strength.
Solution Approach 2:
The tibial prosthetic component utilizes a composite construction with a metal base portions and bridge structure, potentially combined with cement or other bonding materials at the interface with bone. This composite approach enhances both the structural integrity of the connecting bridge and the attachment strength at the tibial eminence by distributing stresses across multiple materials with complementary properties.
3Area of stationary object
If an elevated bridge configuration is used to span the intercondylar passage, then the width of the passage can be increased and compressive forces distributed across a larger area, but the device complexity increases
Solution Approach 1:
The medial and lateral base portions are connected by a single integrated bridge structure that spans the intercondylar passage. This merging of the connecting elements into one unified bridge component simplifies the overall device design compared to using separate connecting structures, while still achieving the goal of distributing compressive forces across a larger area and accommodating the cruciate ligaments.
Data Source
Figure 1
Figure 2~3
Figure 4A~4B
AI summary
A tibial prosthesis (120) comprises a medial base portion (121a) configured to engage a medial surface of a tibia and a lateral base portion (121b) configured to engage a lateral surface of the tibia. At least a portion of the medial and lateral base portions are separated by a passage (138) interposed therebetween. The tibial prosthesis also comprises a bridge (125) coupling the medial base portion and the lateral base portion, wherein at least a portion of the bridge is elevated above a portion of the passage between the medial base portion and the lateral base portion. The bridge may define an underlying area that receives at least a portion of a tibial eminence when the tibial prosthesis is engaged with the tibia, wherein the height of the bridge varies in a superior direction across the passage.