Dual Thread Cannulated Suture Anchor Torque Fixation
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Solution Overview
Problem
Current suture anchors for attaching soft tissue to bone face issues with torque strength and migration due to their design, which often results in weak fixation, especially when the head of the anchor extends into cancellous bone rather than cortical bone.
Innovation Solution
A cannulated suture anchor with a suture-engaging member and dual threads optimized for engagement with cortical bone, allowing for increased torque strength and reduced migration, featuring a driver-compatible design that enables the use of various materials and facilitates bone growth-promoting substances for enhanced fixation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the suture anchor head length is increased to withstand driver torque, then torque strength is improved, but the anchor migrates into cancellous bone resulting in weak fixation
Solution Approach 1:
The suture anchor is divided into functionally distinct segments: a threaded proximal portion for cortical bone engagement and a smooth distal portion for cancellous bone engagement. This segmentation allows each portion to be optimized for its specific function, preventing the migration problem while maintaining torque strength.
Solution Approach 2:
Different portions of the suture anchor have different surface characteristics - the proximal portion has threads for cortical bone engagement while the distal portion is smooth for cancellous bone engagement. This local differentiation of properties solves the contradiction by providing appropriate engagement characteristics at each location.
2Strength
If the suture anchor head length is increased to withstand driver torque, then torque strength is improved, but device complexity increases
Solution Approach 1:
The anchor is segmented into threaded and smooth portions, allowing torque strength to be achieved through the threaded section without requiring an excessively long head. This reduces overall device complexity while maintaining necessary strength.
Solution Approach 2:
Instead of increasing head length in one dimension to achieve torque strength, the solution uses dual-threaded configuration that engages cortical bone in a different dimensional relationship, achieving torque transmission without proportional increase in head length.
3Reliability
If dual threads are used to optimize cortical bone fixation, then migration is prevented, but manufacturing precision requirements increase
Solution Approach 1:
The dual-threaded configuration is confined to a specific proximal portion of the anchor rather than the entire length. This segmentation allows precise thread formation only where needed for cortical engagement, reducing overall manufacturing complexity while maintaining fixation stability.
Data Source
Figure 1A~1B
Figure 1C~1D
Figure 2A~2B
AI summary
A cannulated suture anchor includes a suture-engaging member formed therein and is configured to receive a suture around it such that trailing ends of the suture can extend through the suture anchor. The suture anchor can also include at least a proximal portion having dual threads to facilitate engagement with bone.