Deployable Bone Anchors With Living Hinges for Cancellous Fixation
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Solution Overview
Problem
Conventional bone anchors disrupt healthy cancellous bone during insertion and may migrate due to inadequate fixation, often requiring a one-size-fits-all approach that can lead to unnecessary removal of healthy bone.
Innovation Solution
Deployable bone anchors with a living hinge mechanism that allows radial expansion and contraction, enabling selective engagement with cancellous bone to prevent migration and rotation, and can be customized to fit the specific condition of the patient's bone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If press-fitting is used to insert the bone anchor into cancellous bone, then fixation strength is improved, but healthy cancellous bone is disrupted and removed
Solution Approach 1:
The bone anchor transitions from a compressed insertion state to an expanded fixation state. During insertion, the bone anchor is compressed to fit through the bone tunnel. Once positioned, it expands radially to engage the cancellous bone, providing fixation strength without requiring aggressive press-fitting that would disrupt healthy bone.
Solution Approach 2:
The bone anchor changes its physical dimensions from a smaller insertion profile to a larger expanded profile. This parameter change allows the anchor to be inserted through a prepared tunnel and then expand to engage the cancellous bone, achieving fixation without the need for forceful press-fitting that would damage surrounding healthy bone.
2Ease of manufacture
If the bone anchor is designed with fixed geometry, then manufacturing is simplified, but adaptability to different patient bone conditions is reduced
Solution Approach 1:
The bone anchor incorporates expandable elements that allow it to adapt its geometry after insertion. The expandable distal end and adjustable axial length enable customization to match different patient bone conditions, while the base design remains standardized for easy manufacturing.
Solution Approach 2:
The bone anchor is divided into functional segments: a standardized body for manufacturing, an expandable distal end for adaptation, and adjustable axial length features for customization. This segmentation allows the majority of the device to be manufactured uniformly while specific portions can be adjusted or expanded to fit individual patient needs.
3Stability of the object's composition
If the bone anchor is inserted deeply into the bone tunnel, then fixation stability is improved, but the risk of backward migration increases
Solution Approach 1:
The bone anchor expands radially after insertion to engage the cancellous bone laterally. This radial expansion creates mechanical interlocking with the bone, providing both fixation stability and preventing backward migration without requiring the anchor to be driven deeply into the bone tunnel.
Solution Approach 2:
Instead of relying solely on axial insertion depth for stability, the bone anchor engages the bone in the radial dimension through expansion. This dimensional change from axial to radial engagement provides fixation stability and prevents backward migration by creating lateral mechanical interlocking with the cancellous bone.
4Reliability
If bone cement is used to prevent displacement, then fixation reliability is improved, but the complexity of the procedure and potential for bone damage increases
Solution Approach 1:
The invention eliminates the need for bone cement by using the expandable bone anchor itself to provide fixation. The anchor's expansion mechanism creates direct mechanical engagement with the cancellous bone, removing the intermediate step of bone cement application and reducing procedural complexity and potential complications.
Solution Approach 2:
The bone anchor is self-fixating through its expansion mechanism. When expanded, it creates mechanical interlocking with the cancellous bone without requiring additional materials like bone cement. The anchor serves its own fixation function, simplifying the procedure and reducing the risk of bone damage associated with cement application.
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 deployable bone anchors provide immediate fixation, minimize disruption to healthy bone, and can be easily removed without further damaging cancellous bone during revision procedures.
Implementation Method 1
a living hinge portion configured to allow the wings to flex when the second attachment member and the second end of the implantable body are pulled toward each other by the deployment device
Data Source
Figure 1
Figure 2A~2B
Figure 2C
AI summary
A deployable bone anchor (150, 800) comprises an implantable body (152, 802) comprising a first end comprising a first attachment member (806) to couple to a prosthetic component and a second attachment member (807) to couple to a deployment device, a second end for insertion into bone that comprises a third attachment member (808) to couple to the deployment device, and a sidewall (804) that comprises a living hinge portion to flex when the second and third attachment members are pulled toward each other by the deployment device. A method of implanting a prosthetic component, not part of the claimed invention, comprises forming a bore in a surface of a bone, inserting a distal end of a deployable bone anchor into the bore, attaching a deployment device to a proximal end of the deployable bone anchor, radially expanding the deployable bone anchor with the deployment device, detaching the deployment device, and attaching a prosthetic component to the deployable bone anchor.