Cannulated Drill Bit With Offset Cutting Edge
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Solution Overview
Problem
Current drill bits used in orthopedic surgery, such as for double bundle ACL reconstruction, are limited in their ability to position the graft tunnel hole close to the medial femoral condyle due to their symmetrical axis of rotation, leading to potential interference with the condyle and the need for additional protective measures.
Innovation Solution
A cannulated drill bit with a radially offset cutting edge, where the distal cutting portion extends outside the periphery of the proximal end for a portion of the circumference, allowing closer proximity to the medial femoral condyle and enabling the drill bit to pass closer to the anatomically advantageous location.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a standard drill bit with symmetrical axis of rotation is used, then the drill bit can be easily manufactured and operated, but the drill bit cannot be positioned close enough to the medial femoral condyle to optimize tunnel placement
Solution Approach 1:
The drill bit features an asymmetric design where the cutting edge is offset from the central axis of rotation. Specifically, the cutting edge is positioned radially outward on one side of the axis, creating an asymmetric geometry that allows the drill bit to be positioned closer to the medial femoral condyle while maintaining proper cutting function. This asymmetric configuration enables optimized tunnel placement without requiring complex additional components.
2Manufacturing precision
If the drill bit is positioned closer to the medial femoral condyle to optimize tunnel location, then better surgical outcomes are achieved, but the risk of damaging the condyle increases
Solution Approach 1:
The asymmetric positioning of the cutting edge relative to the rotation axis creates a controlled offset distance. This allows the drill bit to approach closer to the medial femoral condyle (optimizing tunnel placement) while the asymmetric geometry inherently limits how close the cutting edge can get to the condyle, preventing damage. The design thus simultaneously achieves both close positioning and safety.
3Object-affected harmful factors
If protective shields are used to prevent damage to the medial condyle, then condyle protection is improved, but the surgical procedure becomes more complicated
Solution Approach 1:
The invention extracts and eliminates the need for separate protective shields by integrating the protection function directly into the drill bit geometry. The asymmetric cutting edge design inherently prevents condyle damage through its geometric constraints, removing the need for additional protective components and simplifying the surgical procedure while maintaining condyle protection.
4Manufacturing precision
If a thinner drill bit is used to reduce clearance requirements, then closer positioning to the condyle is possible, but the structural strength of the drill bit is reduced
Solution Approach 1:
The asymmetric design allows the drill bit to achieve close positioning to the condyle without requiring a reduction in overall drill bit diameter. The offset cutting edge creates an effective clearance that is smaller than the full drill bit radius, enabling close positioning while maintaining adequate drill bit strength and structural integrity through the full diameter design.
Data Source
AI summary
A drill bit has a cylindrical proximal end coupled to a driving device with a central axis of rotation about which the proximal end rotates. A distal portion of the drill bit is a cutting device attached to the proximal end in such a way that it extends outside the periphery of the proximal end for a distance less than the entirety of the circumference of the proximal end. A guide wire extends through a passageway in the bit and is provided to create a pilot hole before the distal portion enlarges that hole. With this configuration of the cutting device, it is possible to position the cutting device in the distal portion in a direction facing away from the medial femoral condyle so that the proximal end of the drill bit can slide past the medial femoral condyle, with its axis of rotation much closer to that condyle than would be the case in prior art drill bits.