Flush Anchor Collet Swaging for Accurate Tensioning
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Solution Overview
Problem
Prior art medical implants lack accurate provisional tensioning capabilities, leading to unpredictable and irreversible tension settings, and fail to account for tension loss over time, especially in soft tissues, and do not allow for cyclic loading assessments to prevent excessive tension application.
Innovation Solution
A modular orthopedic device with a bone anchor system that includes a housing, a collet, and a sleeve, allowing for axial movement to swage the collet around a tensile member, enabling provisional and permanent tensioning with minimally-invasive access, using a small and low-profile design to prevent stress-shielding and soft tissue hang-up, and allowing for load cycling and re-tensioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If standard suture anchors are used with manual tensioning, then the procedure is simple and quick, but the tension setting is inaccurate and irreversible
Solution Approach 1:
A tensioning device acts as an intermediary between the surgeon and the suture anchor system. This device includes a collet that grips the suture and a ratchet mechanism that provides controlled, incremental tension advancement. The intermediary device translates manual surgeon input into precise, measurable tension increments while preventing overload through the ratchet's one-way engagement feature.
Solution Approach 2:
The patent replaces the purely manual mechanical tensioning system with a hybrid system incorporating a mechanical ratchet mechanism. The ratchet mechanism substitutes for manual estimation by providing predetermined tension increments through its engagement teeth, which allow controlled advancement in discrete steps while preventing backward movement or overload.
2Strength
If high tension is applied to ensure adequate ligament repair, then the repair strength is improved, but the risk of excessive tension and tissue damage increases
Solution Approach 1:
The tensioning system transitions from a static, all-or-nothing tensioning approach to a dynamic, incremental process. The ratchet mechanism enables step-by-step tension application where the surgeon can advance tension in controlled increments, pause to assess tissue response, and reverse or adjust if necessary. This dynamic approach allows optimization of tension within safe limits while achieving adequate repair strength.
Solution Approach 2:
The ratchet mechanism provides beforehand cushioning against excessive tension by its inherent one-way engagement design. The ratchet teeth prevent backward movement and overload, acting as a mechanical safety feature that cushions against accidental over-tensioning. This protective mechanism is built into the system before tensioning begins, preventing harmful effects rather than merely responding to them.
3Reliability
If the anchor device is made larger to provide more secure anchoring, then the anchoring reliability is improved, but the invasiveness of the procedure increases
Solution Approach 1:
The anchor system employs a nested configuration where the collet is positioned inside the anchor body, and the suture passes through the central bore of the collet which is itself within the anchor housing. This nested arrangement maximizes the functional components within a compact footprint, providing secure anchoring capabilities without increasing the overall device size or surgical invasiveness.
Solution Approach 2:
The invention transitions from increasing size in one dimension to achieving reliability through three-dimensional optimization. The anchor features a hollow cylindrical body with internal threading, a centrally positioned collet with radial gripping surfaces, and a suture path that utilizes the internal volume. This dimensional optimization provides secure anchoring through spatial arrangement rather than sheer size, maintaining minimally invasive characteristics.
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
Enables accurate and repeatable tensioning of tensile members, allowing for provisional and permanent securement with minimal invasive procedures, preventing tension loss and ensuring the tension remains within acceptable ranges during joint motion, thus improving surgical precision and reducing complications.
Implementation Method 1
movement of the sleeve from the first position to the second position will cause the exterior interior surface of the sleeve to bear against the exterior surface of the collet, causing the collet to swage radially inwards around and against the tensile member
Implementation Method 2
at least one of the exterior surface of the collet and the interior surface of the sleeve is tapered and the sleeve and the collet are arranged such that movement of the sleeve from the first position to the second position will cause the exterior interior surface of the sleeve to bear against the exterior surface of the collet
Data Source
AI summary
An apparatus for anchoring a tensile member to bone includes a housing with first and second ends and a hollow interior space. A collet is disposed in the interior space, the collet defining a central bore for accepting a tensile member therethrough, and an exterior surface. A sleeve has opposed interior and exterior surfaces and is disposed in the interior space axially adjacent to the collet, and is movable axially between first and second positions. At least one of the exterior surface of the collet and the interior surface of the sleeve is tapered and the sleeve and the collet are arranged such that movement of the sleeve from the first position to the second position will cause the interior surface of the sleeve to bear against the exterior surface of the collet, causing the collet to swage radially inwards around and against the tensile member, without moving axially.