Intramedullary Nail Curvature Adaptation for Tibia Insertion
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Solution Overview
Problem
Existing intramedullary nails are not suitable for use in linear, tubular bones like the tibia due to their large angle between the proximal and distal ends, making them difficult to insert without excessive force.
Innovation Solution
An intramedullary nail with a central section comprising two curved sections of different radii, forming a small angle (9°-12°) between the tangents at the end points, allowing optimal adaptation to the medullary canal of linear tubular bones, with adjustable lengths and locking mechanisms for secure placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the proximal end and distal end are connected by several curved segments forming a large angle, then the nail can be inserted into medullary spaces, but it becomes unsuitable for linear tubular bones like the tibia
Solution Approach 1:
The patent changes the geometric parameters of the nail by reducing the angle between tangents at the end points of the central section from the conventional large angle to a small angle (9°-12°). This parameter modification allows the nail to adapt to linear tubular bones while maintaining insertion capability through the curved sections
2Stability of the object's composition
If a large angle is formed between the proximal and distal ends, then the nail structure is stable, but excessive force is required for insertion
Solution Approach 1:
The patent divides the central section into multiple curved segments with different radii of curvature. This segmentation allows the nail to maintain structural stability through the curved geometry while reducing the angle between end tangents to minimize insertion force requirements
3Device complexity
If the central section has a single curved section, then the structure is simple, but it cannot be optimally adapted to the medullary canal
Solution Approach 1:
The patent segments the central section into multiple curved sections with different radii of curvature (first curved section with larger radius, second curved section with smaller radius). This segmentation enables optimal adaptation to the medullary canal geometry while maintaining reasonable structural complexity
Solution Approach 2:
The patent applies different radii of curvature to different sections of the central section. The first curved section has a larger radius for gradual transition, while the second curved section has a smaller radius for better fit in the medullary canal, creating local quality variations that optimize overall adaptation
Data Source
AI summary
An intramedullary nail, particular for use with a tibia, may have a proximal end part, a distal end part adapted to be introduced into a medullary space, and a central section. The central section includes a first curved section having a first length with a first radius of curvature, and a second curved section having a second length shorter than the first length and a second radius of curvature smaller than the first radius of curvature. The second radius of curvature may be less than the first radius of curvature. The intramedullary nail also includes a central axis. Tangents at two end points of the central section, including the first and second curved sections, enclose an angle gamma between about 9° and about 12°. The intramedullary nail may have a total length ranging from 200 to 500 mm.