Intramedullary Nail with Interlocked Buttress Member for Fracture Stabilization
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Solution Overview
Problem
Current methods for fixing pertrochanteric fractures near the end of the femur, such as sliding hip screws and intramedullary nails with lag screws, often result in unsatisfactory outcomes due to loss of reduction, damage to abductor muscles, and the Z-effect phenomenon, where screws migrate during physiologic loading.
Innovation Solution
A system involving an intramedullary nail interlocked with a buttress member, such as a bone plate, provides enhanced stabilization by using a fin nail with a leading section and a trailing section, along with oblique and transverse fasteners to secure the fracture, reducing the need for distal fasteners and minimizing muscle damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a sliding hip screw is used to stabilize intertrochanteric fractures, then the fracture can be stabilized, but loss of reduction occurs and extensive soft tissue dissection is necessary
Solution Approach 1:
The fixation system is divided into separate functional components: an intramedullary nail for internal fixation and a bone plate for external stabilization. This segmentation allows each component to address specific stabilization needs while reducing the risk of loss of reduction through the interlocked configuration.
Solution Approach 2:
The patent combines two fixation approaches (intramedullary nailing and bone plating) into a single integrated system where the nail and plate are interlocked through fasteners. This merging provides comprehensive stabilization while maintaining reduction, overcoming the limitations of single-component devices.
2Stability of the object's composition
If a lag screw is used in intramedullary nail fixation, then the fracture can be stabilized, but the lag screw may protrude laterally during fracture settling and damage abductor muscles
Solution Approach 1:
The harmful lag screw component is extracted from the fixation system and replaced with a bone plate that provides external stabilization without protruding into the soft tissue. The bone plate achieves fracture stabilization through its interlocked configuration with the nail while avoiding muscle damage.
Solution Approach 2:
The bone plate acts as an intermediary between the intramedullary nail and the fracture site, providing additional stabilization without directly contacting or damaging the abductor muscles. The plate distributes loads and maintains reduction while protecting soft tissues.
3Stability of the object's composition
If a lag screw is used in intramedullary nail fixation, then the fracture can be stabilized, but the lag screw may exhibit Z-effect phenomenon and migrate during physiologic loading
Solution Approach 1:
The fixation system separates the stabilization function into two independent components (nail and plate) that work together through interlocking fasteners. This segmentation eliminates the Z-effect phenomenon by removing the sliding lag screw mechanism that causes migration during physiologic loading.
Solution Approach 2:
Instead of using a sliding lag screw that can migrate, the patent inverts the approach by using a fixed bone plate that provides stable external stabilization. The plate's rigid connection to the bone and its interlocking with the nail prevent the migration problem inherent in sliding screw designs.
4Stability of the object's composition
If distal fasteners are used to secure the intramedullary nail, then the nail can be stabilized, but more muscle damage occurs
Solution Approach 1:
The need for distal fasteners is extracted and eliminated by using the bone plate to provide external stabilization. The plate compensates for the stabilization function that would otherwise require distal fasteners, thereby preventing additional muscle damage in that region.
Solution Approach 2:
The bone plate serves multiple functions: it provides external stabilization, compensates for the absence of distal fasteners, and protects soft tissues. This multi-functionality eliminates the need for additional fasteners that would cause muscle damage while maintaining comprehensive nail stabilization.
Data Source
AI summary
System, including methods, apparatus, and kits, for fixing a bone using an intramedullary nail interlocked with a buttress member disposed on the bone.