Bone Fixation Device with Rotational Member for Oblique Fractures
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Solution Overview
Problem
Stable fixation of bone segments with oblique contact surfaces is challenging due to sliding and instability under axial loading, leading to potential shortening, non-union, or mal-union, which can result in pain, loss of function, and arthritis.
Innovation Solution
A bone fixation device comprising an elongated plate with slots and holes for screws, combined with a rotational member that includes tabs to prevent movement, providing secure alignment and stabilization of oblique fractures by applying torque and surface features to prevent rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If simple apposition of bone surfaces is used for oblique fractures, then the procedure is simple, but the fixation is unstable and sliding occurs under axial loading
Solution Approach 1:
The fixation plate is divided into multiple functional segments: slots for compression screws that allow independent adjustment of each bone segment, and additional holes for stabilizing screws. This segmentation enables separate control of alignment and compression, resolving the contradiction between simple application and stable fixation of oblique fracture surfaces.
Solution Approach 2:
The slots in the fixation plate provide dynamic adjustability, allowing the bone segments to be positioned and compressed independently along the oblique fracture line. This dynamic capability enables the system to adapt to the specific geometry of oblique fractures while maintaining stability under axial loading, overcoming the limitation of simple rigid apposition.
2Reliability
If bone screws are tightened immediately to secure alignment, then stable fixation is achieved, but adjustment and proper alignment become difficult
Solution Approach 1:
The slots are designed to allow preliminary positioning and alignment of bone segments before final tightening. The compression screws can be loosely inserted first to enable adjustment, then progressively tightened to achieve both proper alignment and stable fixation. This preliminary action sequence resolves the contradiction between ease of alignment and stability.
Solution Approach 2:
The system transitions from a dynamic state (loose screws allowing adjustment) to a static state (tightened screws providing stability). The slots maintain adjustability during the alignment phase, then enable secure fixation when the screws are tightened, allowing the system to satisfy both ease of operation and reliability requirements at different stages.
3Reliability
If additional components like rotational members are added to prevent movement, then stability is improved, but device complexity increases
Solution Approach 1:
The rotational member is integrated with the fixation plate through a shared axis and mounting structure, combining two functional elements (plate for compression and rotational member for stabilization) into a unified assembly. This merging approach provides enhanced stability against rotational and translational movements while minimizing the increase in overall device complexity compared to completely separate components.
Solution Approach 2:
The fixation plate serves multiple functions: it provides the structural base for compression, contains slots for alignment adjustment, and integrates the rotational member for stabilization. This multi-functionality reduces the need for entirely separate components, achieving improved movement prevention while controlling device complexity through functional integration.
Data Source
AI summary
A bone fixation device includes an elongated bone fixation plate and a rotational member that are secured to an oblique fractured bone. The fixation plate can be secured to the bone across the fracture. The rotation member can include two tabs that extend around opposite sides of the bone. The bone segments can be aligned and secured to the fixation plate. The rotation member can then be rotated so that the tabs physically contact and prevent movement of the bone segments.