Knee Component Orbital Interface Boss
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Solution Overview
Problem
Knee joint prostheses often lack adaptability to individual patient anatomy, particularly due to variations in femoral canal alignment and valgus angles, which can complicate implantation and affect the accuracy of simulating natural knee motion.
Innovation Solution
The introduction of an orbital interface boss with non-parallel terminal end surfaces and coupling members that can be rotated to achieve multiple angular orientations, allowing for precise alignment and secure coupling with femoral and tibial components to accommodate varying valgus angles and patient-specific anatomy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If knee joint prosthesis uses fixed alignment stems, then manufacturing and implantation are simplified, but adaptability to individual patient anatomy (femoral canal offset, valgus angles) is reduced
Solution Approach 1:
The prosthesis is divided into modular components: a femoral stem with engagement portion, a separate indexing boss with coupling members, and a tibial component. This segmentation allows the indexing boss to provide angular adjustability while the stem provides structural support, resolving the contradiction between adaptability and complexity by distributing functions across modules.
Solution Approach 2:
The indexing boss introduces dynamic adjustability to the otherwise fixed prosthesis structure. The coupling members can rotate and lock at multiple angular positions, allowing the prosthesis to adapt to different patient anatomies (different valgus angles, canal offsets) while maintaining structural integrity through the engagement portions.
2Adaptability or versatility
If knee joint prosthesis uses offset femoral stems with range of valgus angles, then adaptability to patient anatomy is improved, but device complexity and difficulty of implantation increase
Solution Approach 1:
The indexing boss is pre-configured with multiple engagement positions and coupling members that can be rotated to predetermined angular orientations. This preliminary preparation of angular positions allows the surgeon to simply rotate the boss to the appropriate angle and lock it, rather than requiring complex pre-planning or custom fabrication for each patient anatomy.
Solution Approach 2:
The indexing boss acts as an intermediary component between the femoral stem and tibial component. It mediates the angular adjustment function, allowing the surgeon to achieve proper alignment by rotating the boss to the correct angle, while the engagement portions ensure secure mechanical connection. This intermediary simplifies the implantation process compared to using custom-angle stems.
3Adaptability or versatility
If indexing boss has non-parallel terminal end surfaces for multiple angular orientations, then adaptability to patient anatomy is improved, but manufacturing precision requirements increase
Solution Approach 1:
The indexing boss features asymmetric non-parallel terminal end surfaces with coupling members positioned at specific angular orientations. This asymmetric geometry is deliberately designed to provide discrete angular positions (e.g., 0°, 15°, 30°, 45°) rather than requiring continuous precision. The asymmetry allows for standardized manufacturing at discrete angles, reducing the overall precision burden compared to creating perfectly parallel surfaces that would require higher precision to achieve the same angular adjustability.
Data Source
AI summary
A knee prosthesis including a knee component and an indexing boss. The knee component includes a first engagement portion. The indexing boss includes a first terminal end surface, a second terminal end surface, and a second engagement portion at the second terminal end surface. The first terminal end surface and the second terminal end surface are arranged along non-parallel planes. The first and the second engagement portions are configured to selectively couple together at a plurality of rotational orientations to attain a corresponding plurality of angular orientations of the indexing boss relative to the knee component due to the first and the second terminal end surfaces being arranged along non-parallel planes.