Locking Instrument Assembly for Intramedullary Fixation
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Solution Overview
Problem
Existing orthopaedic instruments lack stability and versatility in fixing instruments relative to an intramedullary reference axis, often requiring secondary fixation devices like bone spikes or pins, and restrict the length of intramedullary instruments, which limits their effectiveness in surgeries involving deformities or unusual anatomical conditions.
Innovation Solution
A locking instrument assembly comprising an inner collet, intermediate body, and knob that applies a clamping force to an intramedullary device, allowing for modular connection and adjustment of cutting guides and alignment guides relative to the intramedullary reference axis, enabling rotation and axial adjustment without the need for secondary fixation devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bone spikes or pins are used for fixation, then the instrument can be fixed to bone, but the stability and versatility are insufficient and additional fixation devices are required
Solution Approach 1:
The patent combines the intramedullary reference instrument with the guide assembly into a single integrated unit. The guide assembly is rigidly connected to the intramedullary instrument, eliminating the need for separate fixation devices like bone spikes or pins. This merging of components achieves stable fixation while reducing device complexity.
Solution Approach 2:
The intramedullary reference instrument serves multiple functions: it provides internal referencing, establishes the mechanical axis, and acts as the primary fixation device. By making the reference instrument multi-functional, the patent eliminates the need for additional fixation devices while maintaining reliability.
2Reliability
If the intramedullary instrument length is restricted, then the instrument can be connected through threaded connection, but the stability is limited and the surgeon cannot optimize the intramedullary instrument length
Solution Approach 1:
The patent transitions from fixed-length intramedullary instruments to adjustable-length instruments. The surgeon can optimize the length of the intramedullary instrument based on patient-specific anatomy and surgical requirements, while the rigid connection maintains stability. This dynamic adjustment capability resolves the contradiction between stability and adaptability.
3Ease of operation
If the guide assembly is removed before resection, then clearance is provided for the cutting instrument, but the stability gained through connection is lost
Solution Approach 1:
The patent segments the guide assembly into modular components that can be selectively removed or retained. The cutting guide portion can be removed to provide clearance for the cutting instrument, while the intramedullary reference instrument remains in place to maintain stability. This segmentation allows the surgeon to optimize both clearance and stability.
4Strength
If cutting guides are fixed to bone using bone spikes, screws, drills and pins, then the cutting guide can be securely attached, but the surgical complexity increases and primary fixation is compromised
Solution Approach 1:
The patent merges the guide assembly with the intramedullary reference instrument into a single rigidly connected unit. This integration provides secure attachment strength while eliminating the need for additional bone fixation devices like spikes, screws, drills, and pins, thereby reducing surgical complexity.
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 solution provides stable and versatile fixation of orthopaedic instruments, allowing for precise resection maneuvers without the need for additional fixation devices, reducing surgical complexity and improving the accuracy of bone resections by maintaining primary fixation and allowing for oblique cutting planes.
Implementation Method 1
the inner collet applies a clamping force to the intramedullary device
Data Source
AI summary
A locking instrument assembly for use in conjunction with an intramedullary device is disclosed. The locking instrument assembly includes an inner collet, an outer body, and a knob. The inner collet has a collar and a fastener member. The knob engages the fastener member to press the outer body against the collar. As the knob mates with the fastener member, the collar applies a clamping force to the intramedullary device.