Tapered Compression Screw Angulated Fixation
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Solution Overview
Problem
Current surgical fixation methods for small bones and osteotomies, such as distal interphalangeal joint fusion, often result in sub-optimal outcomes due to lack of functional flexion and increased risk of complications, particularly in phalangeal joints of the hands and feet, where existing compression screws fail to provide adequate compression and angulation for optimal healing.
Innovation Solution
A compression screw with a slowly tapered threaded leading portion, an unthreaded intermediate portion, and a sharply tapered threaded head, designed for percutaneous insertion to minimize tissue damage and facilitate early mobilization, allowing for angled implantation and compression across the joint to enhance fusion and prevent rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a straight compression screw is used for distal interphalangeal joint fusion, then compression across the joint is achieved, but functional flexion and grip strength improvement are not obtained
Solution Approach 1:
The screw is designed with an asymmetric angular orientation where the proximal end is angled at a different angle than the distal end. This asymmetric angular configuration allows the screw to provide both compression across the joint and functional flexion, resolving the contradiction between fusion reliability and functional flexion capability.
2Ease of operation
If k-wire fixation is used to achieve angled fusion, then functional flexion is improved, but the immobilization protocol fails and complications increase
Solution Approach 1:
The patent replaces the mechanical k-wire fixation system with a compression screw that integrates compression and angular fixation capabilities. This substitution eliminates the need for separate immobilization protocols and reduces complications while maintaining functional flexion, thereby improving both reliability and ease of operation.
3Force
If a compression screw with constant diameter is used, then compression across the joint is provided, but angulation and rotation inhibition are insufficient
Solution Approach 1:
The screw incorporates asymmetric angular features at different portions of its length, allowing it to provide both compression force and angular stability. The varying angles at proximal and distal ends enable the screw to resist rotation and maintain proper angulation while delivering compression, thus resolving the contradiction between compression force and angular stability.
4Reliability
If traditional insertion methods are used, then compression screw fixation is achieved, but soft tissue, cartilage and vascular damage occurs
Solution Approach 1:
The screw is divided into distinct functional segments: a threaded portion for bone engagement, an unthreaded intermediate portion for smooth insertion, and a head portion for compression. This segmentation allows the unthreaded intermediate section to minimize soft tissue and cartilage damage during insertion while the threaded portions provide reliable fixation, thus resolving the contradiction between fixation reliability and tissue preservation.
Data Source
AI summary
The present invention relates to a device and system for surgical fixation of small bones, small bone fragments, and osteotomies and more particularly to compression screw having an elongated and spiked tapered threaded leading portion which is joined to a section that is free from threads and a threaded trailing portion and more sharply tapered head which has threads that continue from the threads of the leading portion.