Cannulated Orthopedic Anchor for Inward Bone Particulate Flow
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Solution Overview
Problem
Conventional orthopedic screws used for SI joint fusion often fail to effectively distribute bone particulate within the joint, leading to inadequate bone ingrowth and slower fusion rates, as material is primarily directed outward, neglecting the interior regions of the implant.
Innovation Solution
The development of an orthopedic anchor with an inner geometry that includes flutes and channels to direct bone particulate inward, promoting bone ingrowth by distributing it along the length of the anchor, combined with a porous outer structure to facilitate fusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional orthopedic screws are used, then the screw structure is simple and easy to manufacture, but bone particulate is not effectively directed into the inner regions of the screw, limiting bone ingrowth and fusion
Solution Approach 1:
The screw structure is segmented into multiple functional zones including outer threads for bone engagement, inner flutes for particulate transport, and apertures for material exchange. This segmentation allows each zone to perform its specific function optimally while working together to achieve effective bone fusion.
Solution Approach 2:
Different regions of the screw are given different properties: the outer surface has threads for mechanical anchoring, the inner surface has flutes with specific geometries for directing bone particulate, and strategic apertures are placed to facilitate material flow. Each local region is optimized for its specific function to collectively improve bone ingrowth.
2Productivity
If bone graft is placed within the joint using conventional screws, then fusion can occur, but the process is slow and bone particulate does not effectively reach inner regions of the implant
Solution Approach 1:
The screw is pre-configured with flutes and channels that are ready to direct bone particulate during insertion and healing. The geometry is designed in advance to automatically channel materials to optimal locations without requiring additional surgical intervention or manual placement steps.
Solution Approach 2:
The screw structure itself performs the function of directing and distributing bone particulate through its integrated flute system. The design enables the implant to self-direct materials during the healing process, eliminating the need for external assistance or complex delivery mechanisms.
3Manufacturing precision
If the screw has a simple cylindrical structure, then manufacturing is easy, but bone particulate distribution within the screw is inadequate for effective fusion
Solution Approach 1:
The flute structure is nested within the screw body, with channels positioned concentrically or eccentrically within the cylindrical form. This nesting allows complex internal geometries to be achieved while maintaining the overall simple external shape that is easy to manufacture and implant.
Solution Approach 2:
The design adds internal dimensional complexity through flutes and channels without significantly increasing external dimensions. The bone particulate distribution is controlled in the radial and axial dimensions within the screw, enabling precise material placement while maintaining a compact, manufacturable form.
Data Source
AI summary
An embodiment includes a sacroiliac joint bone anchor system comprising: a bone anchor including an outer surface and an inner surface; wherein (a)(i) the outer surface includes a proximal third, a middle third, and a distal third, (a)(ii) the middle third of the outer surface includes at least one aperture that couples the outer surface to the inner surface; (a)(iii) the proximal third of the outer surface includes proximal threads, and (a)(iv) the distal third of the outer surface includes distal threads; wherein (b)(i) the bone anchor is cannulated, (b)(ii) a channel is located on the inner surface, (b)(iii) the channel extends from a proximal third of the inner surface to a distal third of the inner surface, and (b)(iv) the channel provides at least one half a rotation about a long axis of the bone anchor.