Adjustable Bone Fixation Device for Femoral Neck Shortening
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Solution Overview
Problem
Femoral neck fractures in osteoporotic patients often result in femoral neck shortening during healing, leading to complications such as bone screw penetration of the femoral head and migration, causing pain and the need for additional surgery due to the inability of traditional compression bone screws to adapt to bone shortening.
Innovation Solution
A sliding device comprising an external screw with a channel and an internal screw with a pushing rod section and a length adjuster, allowing for adjustable sliding distance to accommodate femoral neck shortening, preventing screw penetration and migration by allowing precise adjustment of screw position relative to the bone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If multiple compression bone screws are inserted parallel to each other, then the screws can be easily inserted and positioned, but the screws will retreat during the healing process due to femoral neck shortening
Solution Approach 1:
The patent applies the dynamics principle by designing a sliding mechanism that allows the internal screw to move relative to the external screw along the longitudinal axis. This dynamic adjustment capability enables the fixation device to adapt to femoral neck shortening during healing, preventing screw retreat while maintaining ease of insertion through the standardized screw structure
2Adaptability or versatility
If multiple compression bone screws are inserted in a divergent manner, then the screws can accommodate femoral neck geometry, but the screws may penetrate the femoral head due to inability to adapt to shortening
Solution Approach 1:
The sliding mechanism enables dynamic adjustment of the internal screw position relative to the external screw, allowing the divergent screw configuration to maintain its geometric adaptability while preventing harmful penetration into the femoral head during the healing process
3Productivity
If traditional compression bone screws are used, then the surgical procedure is simple and quick, but the screws cannot adapt to femoral neck shortening causing migration and complications
Solution Approach 1:
The sliding mechanism provides dynamic adaptability to femoral neck shortening while maintaining relatively simple surgical insertion procedures, thus improving reliability without significantly compromising surgical efficiency
Solution Approach 2:
The nested structure of internal screw within external screw allows for compact design that maintains surgical efficiency while enabling adaptive movement to prevent screw migration and complications
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The device effectively reduces complications associated with femoral neck fractures by allowing for precise adjustment of screw position, preventing screw penetration and migration, thereby minimizing pain and the need for additional surgery.
Implementation Method 1
the at least one groove is configured to accommodate the at least one protrusion of the first inner side, and the first pushing rod section is configured to slide within the first channel along the longitudinal axis
Data Source
AI summary
A device is provided. The device includes an external screw includes a first channel extending along a longitudinal axis, and the first channel including a first inner side including at least one protrusion; and an internal screw includes a first pushing rod section including a first threaded section and at least one groove, the at least one groove is configured to accommodate the at least one protrusion of the first inner side, and the first pushing rod section is configured to slide within the first channel along the longitudinal axis.