Femoral Stem Offset Mechanism for In Situ Gap Assessment
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Solution Overview
Problem
Existing femoral stem offset adjustment systems require significant installation space and are cumbersome, necessitating removal for gap assessment, which is time-consuming and inefficient.
Innovation Solution
A compact femoral stem offset adjustment system with a user adjustment element and stem support that allows 360° rotation and unidirectional sliding, integrated within the thickness of the femur implant, enabling in situ adjustment of offset position and gap assessment without removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a traditional femoral stem offset adjustment system is used, then offset adjustment functionality is provided, but the system requires significant installation space and protrudes beyond the femur implant
Solution Approach 1:
The adjustment mechanism is nested within the thickness of the femur implant itself. The user adjustment element rotates within a receiving structure in the femur support, and the stem support with sliding connection is integrated into this same space, allowing 360° rotation and unidirectional sliding without protruding beyond the implant.
Solution Approach 2:
The adjustment mechanism utilizes the radial thickness dimension of the femur implant rather than requiring additional axial or lateral space. By arranging the rotation and sliding movements within the implant's own thickness, the system achieves compact integration while maintaining full adjustability.
2Measurement precision
If the adjustment system is removed for gap assessment, then accurate flexion and extension gap evaluation is possible, but the process becomes time-consuming and adds workflow steps
Solution Approach 1:
The adjustment system serves multiple functions: it provides offset adjustment during implant positioning and simultaneously enables gap assessment (flexion and extension gap evaluation) while remaining mounted on the femur implant. This eliminates the need to remove the adjustment system for gap measurement.
Solution Approach 2:
The adjustment system remains continuously mounted on the femur implant throughout the surgical workflow, allowing uninterrupted transition from offset adjustment to gap assessment without removal or reinstallation steps.
3Volume of moving object
If a compact adjustment system integrated within the femur implant is used, then installation space is reduced and gap assessment can be performed in situ, but the system complexity increases
Solution Approach 1:
The adjustment system is divided into distinct functional components: a user adjustment element for manual operation, a femur support for mounting on the implant, a stem support for connecting to the stem, and a sliding connection mechanism. Each component has a specific function, making the complex integration manageable and modular.
Data Source
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AI summary
The invention relates to a femoral stem offset adjustment system (1) for adjusting a femur implant (2) in reference to an intramedullary channel (3) of a femur, the adjustment system (1) comprising a femur support (5), a user adjustment element (6), a stem support (7), a first link member (8) rotatably holding the user adjustment element (6) in the femur support (5), a second link member (9) integrally rotatably coupling the user adjustment element (6) and the stem support (7), and a third link member slidably connecting the user adjustment element (6) and the stem support (7), wherein at least two of the first link member (8), the second link member (9) and the third link member, preferably the longitudinal axes thereof, are arranged substantially in a common plane, the plane being perpendicular to the rotational axis.