Suture-retaining device anchor for rotator cuff repair
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Solution Overview
Problem
Current methods for repairing a detached rotator cuff tendon from the humeral head face challenges such as anchor displacement, limited suture availability, and inadequate fixation due to the weak bone structure, leading to issues like 'lift-off' and reduced healing efficiency.
Innovation Solution
A suture-retaining device mechanically coupled with an anchor that is inserted into the cortex of the humerus, providing firm support and allowing multiple sutures to be securely attached, with adjustable length and clamp mechanisms to optimize knot placement and reduce anchor displacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If suture anchors are inserted into the humeral head to secure the rotator cuff tendon, then the tendon can be positioned against the humeral head for healing, but anchor displacement occurs due to the weak and porous bone structure
Solution Approach 1:
The patent transitions from inserting anchors horizontally into the humeral head to inserting anchors vertically into the humeral shaft. This dimensional change allows the anchors to engage with denser cortical bone in the shaft rather than the porous cancellous bone of the head, significantly improving fixation reliability while avoiding the weak bone structure problem.
2Strength
If multiple suture anchors are used to secure the tendon, then the connection becomes more robust, but the limited area of the humeral head restricts the number of anchors that can be placed
Solution Approach 1:
The patent moves the anchor placement location from the limited surface area of the humeral head to the extended surface area of the humeral shaft. This dimensional relocation provides ample space for multiple anchor insertions, enabling robust tendon-bone connections without the spatial constraints of the humeral head.
3Reliability
If the rotator cuff tendon is pulled tight to eliminate lift-off, then healing is improved, but the tension on the suture anchors increases causing anchor displacement
Solution Approach 1:
By relocating anchors to the humeral shaft, the patent creates a more favorable biomechanical lever arm. The increased distance from the tendon insertion point reduces the moment arm and corresponding forces on the anchors, allowing the tendon to be secured with appropriate tension for healing without generating excessive pull-out forces that would cause displacement.
4Reliability
If bone tunnels are formed to attach sutures to bone, then the tendon can be properly positioned for healing, but the already weak bone structure is further weakened and susceptible to breakage
Solution Approach 1:
The patent avoids creating bone tunnels in the humeral head by inserting anchors vertically into the humeral shaft. This dimensional relocation preserves the integrity of the humeral head bone structure while still achieving reliable tendon positioning through the shaft-based anchor system.
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
This solution enhances the stability and robustness of the tendon attachment, minimizing 'lift-off' and enabling the use of smaller sutures for a more secure connection, even when the arm is raised, while allowing for precise adjustment and efficient knotting.
Implementation Method 1
The anchor has a threaded end configured for engagement with a cortex of the humerus to provide firm support for the suture-retaining device
Data Source
AI summary
A rotator cuff tendon injury is repaired using a flexible fastener and an anchor. The flexible fastener is attached to the rotator cuff tendon and also secured to the anchor. The anchor is attached to or supported by various locations on the humerus other than the humeral head, to provide a robust means for holding the rotator cuff tendon in the desired position against the humeral head.