Bone Anchor with Locking Member for Pull-Out Prevention
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Solution Overview
Problem
Existing anchoring systems for securing objects to bones, particularly in osteoporotic bones, face challenges with anchor pull-out and loosening due to inadequate grip and rigidity, often requiring additional aiming guides that complicate installation.
Innovation Solution
An anchoring system comprising an anchoring member with a proximal socket and oblique aperture, paired with a locking member that secures the anchoring member within the bone, using fasteners that match the angulation of the locking member to prevent unscrewing and loosening, and featuring a rough surface for enhanced grip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If expandable mechanisms are used to increase grip in cancellous bone, then the anchor grip is improved, but the bone tissue is crushed and split creating empty rooms that lead to toggling and pull-out
Solution Approach 1:
The anchoring system is divided into two separate functional components: an anchoring member that provides initial bone engagement and a locking member that secures the construct. This segmentation allows each component to perform its specific function optimally without the anchoring member needing to expand and create unstable cavities.
Solution Approach 2:
The locking function is extracted from the anchoring member and implemented as a separate locking member. This allows the anchoring member to focus on providing secure bone engagement while the locking member provides the anti-backout and anti-loosening function, eliminating the need for expandable mechanisms that compromise bone integrity.
2Reliability
If locking mechanisms are added to secure the anchor, then pull-out is prevented, but the construct becomes more complex and may require additional aiming guides
Solution Approach 1:
The locking member is designed to be integrated with the anchoring member through a simple interlocking interface. The locking member features a head that engages with a receptacle on the anchoring member, and a shaft that aligns with the anchoring member's axis, eliminating the need for separate aiming guides or complex alignment procedures.
Solution Approach 2:
The locking member serves multiple functions: it secures the anchoring member against backout, prevents loosening through anti-rotation features, and maintains proper alignment. This multi-functionality is achieved through a single component design that combines locking, alignment, and stabilization features.
3Stability of the object's composition
If bicortical screwing is used to increase rigidity, then the construct stability is improved, but the implant may breakage due to excessive rigidity
Solution Approach 1:
The anchoring member features a threaded distal end for bone engagement and a smooth proximal end for receiving the locking member. This local differentiation of structural properties allows the anchoring member to provide secure fixation in the bone while maintaining flexibility in the proximal region to prevent stress concentration and implant breakage.
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 system effectively secures objects to bones by preventing anchor pull-out and loosening, enhancing reliability without the need for additional aiming guides, particularly in osteoporotic bones, by utilizing an oblique aperture and matching fasteners to maintain torque and grip.
Implementation Method 1
Special features like conical core, self-tapping profile and roughened surfaces of the anchor have been developed to increase the grip to the cancellous bone
Data Source
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AI summary
An anchoring device and method for attaching an object to a bone comprises an anchoring member having proximal and distal ends, with the proximal end being adapted to hold the object to the bone while the distal end is in the bone, and a locking member having proximal and distal ends, with the proximal end adapted to secure the anchoring member into the bone and oppose its pull-out or loosening by stopping its backing or preventing its unscrewing while the distal end is in the bone. Also provided are first and second fasteners, with the first fastener adapted to fit to the proximal end of the anchoring member, and the second fastener adapted to fit to the proximal end of the locking member. The end of the second fastener can have an angle that matches an angle of the locking member.