Bone Screw Pin Insertion for Anti-Migration Charcot Foot Fixation
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Solution Overview
Problem
Existing bone screws for treating Charcot foot suffer from high infection risk and long-term instability due to migration from the initial implant position, which compromises treatment outcomes.
Innovation Solution
A bone screw design with a non-threaded intermediate portion and externally threaded tip and head, featuring at least one transverse hole for pin insertion to prevent migration, along with an insertion instrument for guided pin placement, ensuring stability and minimizing infection risk through reduced incision size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a bone screw is implanted to support bone structure, then mechanical support and weight bearing are improved, but the risk of infection increases and migration occurs
Solution Approach 1:
The bone screw is divided into three distinct portions: a threaded head portion, a non-threaded intermediate portion, and a threaded tip portion. This segmentation allows the screw to provide mechanical support while minimizing infection risk by reducing the size of the incision needed for implantation, as the screw can be inserted through a smaller opening and then expanded or secured within the bone structure.
2Force
If a bone screw is implanted to provide compression, then bone compression and stabilization are improved, but long-term stability deteriorates due to migration
Solution Approach 1:
Different portions of the bone screw have different functional qualities: the head and tip portions are threaded to provide compression and anchoring forces, while the intermediate portion is non-threaded to allow for controlled expansion or securing mechanisms. This local differentiation enables the screw to maintain both compression force and long-term stability by preventing migration through its specialized structural zones.
3Strength
If a large diameter stem is used to support weight, then load bearing capacity is improved, but device complexity and infection risk increase
Solution Approach 1:
The bone screw transitions from a static, uniformly large-diameter structure to a dynamic, multi-zoned structure where the diameter and threading characteristics vary along its length. The threaded head and tip provide anchoring, while the non-threaded intermediate portion allows for controlled insertion and expansion, enabling the screw to achieve load-bearing capacity without requiring a uniformly large diameter throughout, thus reducing overall complexity.
Data Source
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AI summary
The present invention relates to an improved bone screw (1') for the treatment of bone collapses or deformations, such as in the case of the Charcot foot, comprising a non-threaded intermediate portion (2) spaced between a tip portion (3) and a head portion (4) externally threaded; the bone screw (1') further comprising at least one transverse hole (6) arranged for inserting a corresponding at least one pin (7) to prevent the migration of said bone screw (1) when implanted into the bone. The present invention also relates to an insertion instrument (20) for inserting at least one pin (7) into at least one hole (6) of the bone screw (1').