Porous Threaded Fixation Implants for Sacroiliac Stability
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Solution Overview
Problem
Conventional bone screw implants for the sacroiliac joint are vulnerable to rotation and failure due to the natural movement of the joint, leading to instability and hypermobility, necessitating improved devices that provide enhanced fixation and resistance to rotational and pull-out failures.
Innovation Solution
The development of fixation implants with an open network body resembling trabecular bone structure, featuring enhanced bone engagement surfaces and osseo-integration through open and interconnected pores, providing greater stability and bony ingrowth opportunities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional bone screw implants are used for sacroiliac joint fixation, then the joint can be stabilized, but the implants are vulnerable to rotation and failure due to natural joint movement
Solution Approach 1:
The implant incorporates a porous open network body that resembles trabecular bone structure, providing enhanced bone engagement surfaces and osseo-integration. The open and interconnected pores allow for greater bony ingrowth and create mechanical interlocking with the surrounding bone, significantly improving resistance to rotational failure and pull-out forces while maintaining implant stability
Solution Approach 2:
The fixation implant combines different materials with complementary properties: a porous open network body (potentially polymer or metal) integrated with threaded portions and fixation elements. This composite structure provides both the biocompatibility and integration benefits of porous materials and the mechanical strength and rotational resistance of metallic threaded components, resolving the contradiction between stability and rotational failure resistance
2Stability of the object's composition
If typical bone screw type implants are used, then fixation can be achieved, but the small range of motion of the sacroiliac joint is exaggerated leading to hypermobility
Solution Approach 1:
The porous open network body provides extensive bone engagement surfaces that distribute mechanical loads and promote osseo-integration. This enhanced biological fixation, combined with the mechanical interlocking from the porous structure, prevents hypermobility while preserving the natural physiological motion of the sacroiliac joint through improved stress distribution and bone-implant bonding
3Strength
If conventional solid bone screws are used, then fixation is provided, but bone engagement surface area is limited reducing osseo-integration
Solution Approach 1:
The open network body provides an dramatically increased bone engagement surface area compared to solid screws. The open and interconnected pores create numerous contact points and mechanical interlocking features that enhance bone purchase and osseo-integration. This porous structure allows bone to grow into and around the implant, creating strong biological anchoring while distributing mechanical stresses more effectively
Data Source
AI summary
A fixation implant includes a head, a shank and a distal tip, and one or more of the head, shank and distal tip may be cannulated. The shank includes a threaded ingrowth portion extending from the head to the tapered distal tip that includes external threads, and at least one open network body extending along the length of the ingrowth portion. The open network body selected from one or a combination of a helix, an arrangement of trusses, a scaffold of open and interconnected pores, a porous framework of random open and interconnected pores, and combinations of these.