Concentric Suture Anchor Inserter for Stable Eyelet and Suture Tension
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Solution Overview
Problem
Existing suture anchor insertion tools lack efficiency and stability, leading to potential tendon re-tears due to unstable tendon-bone healing caused by oscillation or micro-motion between the tendon and bone.
Innovation Solution
A novel insertion tool with a handle, intermediate and outer shafts, and a rotatable knob system that allows for precise control of the suture anchor's rotation and distal translation, ensuring stable fixation of the anchor body within the bone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a suture anchor is inserted using conventional tools, then the anchor can be implanted in bone, but the tendon-bone fixation becomes unstable due to oscillation or micro-motion during insertion
Solution Approach 1:
The insertion tool employs a dynamic control mechanism where the outer shaft can translate distally relative to the intermediate shaft to advance the anchor body while the intermediate shaft rotates to rotate the anchor. This dynamic coordination allows precise control of both rotation and advancement, preventing oscillation and micro-motion that would compromise fixation stability.
Solution Approach 2:
The intermediate shaft acts as an intermediary component that couples to the anchor body and transmits rotational motion from the handle to the anchor, while the outer shaft serves as a mediator to advance the anchor distally. This intermediary mechanism enables independent control of rotation and advancement, ensuring stable tendon-bone fixation during insertion.
2Productivity
If the anchor body is rotated and advanced simultaneously during insertion, then efficient implantation is achieved, but the eyelet may rotate unintentionally causing misalignment
Solution Approach 1:
The insertion tool is segmented into distinct functional components: the intermediate shaft for rotation control and the outer shaft for advancement control. This segmentation allows the surgeon to independently control the rotational and translational movements of the anchor body, preventing unintentional eyelet rotation while maintaining efficient insertion.
Solution Approach 2:
The tool enables dynamic control where the intermediate shaft rotates to rotate the anchor body and the outer shaft translates distally to advance the anchor. This dynamic independence allows efficient simultaneous operation while maintaining precise eyelet positioning accuracy by controlling each degree of freedom separately.
3Device complexity
If a simple insertion tool is used, then device complexity is reduced, but control over anchor rotation and advancement is insufficient
Solution Approach 1:
The insertion tool uses a nested structure where the inner shaft is concentrically disposed within the intermediate shaft, and the outer shaft is concentrically disposed about the intermediate shaft. This nested design provides a compact, relatively simple tool structure while enabling complex coordinated control of anchor rotation and advancement through the interaction of the nested shafts.
Solution Approach 2:
Despite the relatively simple nested structure, the tool achieves sophisticated control through dynamic interaction: the intermediate shaft rotates relative to the handle to rotate the anchor body, while the outer shaft translates distally relative to the handle to advance the anchor body. This dynamic mechanism provides excellent control over both rotation and translation without excessive structural complexity.
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 tool ensures stable tendon-bone healing by maintaining tension in the sutures and preventing rotation of the eyelet during anchor insertion, enhancing the success of surgical repairs.
Implementation Method 1
a proximal end of the outer shaft may be movably coupled to the handle and to the rotatable knob via at least one spline aligned along the longitudinal axis and via a lead screw thread. Due to such movable coupling, rotation of the rotatable knob preferably drives distal translation of the outer shaft relative to the handle.
Implementation Method 2
the handle may have a rotatable knob coupled thereto for driving rotation of the intermediate shaft relative to the handle via a ring gear engaged with a spur gear. The ring gear and the spur gear may define a gear ratio therebetween such that the anchor body rotates at a different rate than the rotatable knob.
Data Source
AI summary
An insertion tool for inserting a suture anchor into bone includes three concentric shafts coupled to a handle. An intermediate shaft is rotatable relative to the handle to rotate the anchor body. An inner shaft within the intermediate shaft has a distal end for coupling to an eyelet positionable distally of the anchor body. An outer shaft disposed about the intermediate shaft translates distally to advance the anchor body towards the eyelet. A retention suture and at least one repair suture may be coupled to the eyelet such that their free ends are coupled to the handle. The free ends of the retention suture extend within the intermediate shaft and through a space between a ring gear and a spur gear of the handle. During operation, the distance between the handle and the distal end of the inner shaft remains constant so as to maintain tension in the repair suture.