Intramedullary Compression Rod for Small Bone Fractures
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Solution Overview
Problem
Conventional intramedullary rods struggle to fixate and stabilize fractures in smaller diameter long bones, such as the ulna, due to the small bone diameter, which prevents the use of through holes and makes precise alignment of fixation screws difficult.
Innovation Solution
An intramedullary rod with a distal end designed to engage a screw and a proximal end featuring through holes for fixation screws, along with an insertion jig that applies compressive force and aids in correct screw placement, allowing for fixation and compression without precise alignment of the distal screw, and using headless screws to minimize soft tissue damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If through holes are provided in the rod for fixation screws, then the rod can be fixed to the bone, but the rod diameter must be large enough to accommodate through holes
Solution Approach 1:
The rod is divided into two functional zones: the proximal end with through holes for reliable fixation, and the distal end as a solid portion for engagement with the compression device. This segmentation allows each part to serve its specific function without compromising the other.
Solution Approach 2:
Different parts of the rod have different structural qualities - the proximal end has through holes for screw fixation while the distal end remains solid for compression engagement. This local differentiation optimizes each region for its specific purpose.
2Manufacturing precision
If precise alignment of distal end fixation screw is required, then fixation accuracy is improved, but the complexity and difficulty of the procedure increases
Solution Approach 1:
The compression device acts as an intermediary mechanism that translates axial compression forces into precise positioning of the distal end screw. By using the compression device as a mediator, the system achieves accurate alignment without requiring complex pre-alignment procedures.
Solution Approach 2:
The distal end screw is positioned and engaged with the solid portion of the rod before final compression is applied. This preliminary positioning ensures proper alignment is established prior to the compression phase, simplifying the overall procedure.
3Object-affected harmful factors
If headless fixation screws are used, then damage to overlying soft tissues is reduced, but the screws cannot be easily removed or adjusted
Solution Approach 1:
The screw heads are extracted or removed from the fixation screws, creating headless screws that eliminate soft tissue irritation. The screws rely on friction and compression forces for retention rather than protruding heads.
Solution Approach 2:
The absence of screw heads, while potentially making removal more difficult, eliminates the harmful effect of soft tissue irritation and prominence. The compression device provides the necessary retention mechanism, converting the potential disadvantage into a benefit by eliminating soft tissue damage.
Data Source
AI summary
A device and method of stabilizing a fracture of a bone is provided. The device includes an intramedullary rod having a shaped distal end, and an insertion jig detachably connectable to the proximal end of the rod and used with the rod to apply a compressive force to the fracture site. The jig may also be used to correctly place fixation screws in a proximal end of the rod. The device achieves both fixation of the rod to the bone regardless of rod or bone diameter and allows for compression at the fracture site. In addition, fixation of the rod to the bone is accomplished without requiring a precise alignment of a distal end fixation screw. The device uses headless fixation screws, which, when in place, are disposed below cortical surface of bone, reducing damage to overlying soft tissues.