Braided Filament Strand Composition for Suture Strength and Friction
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Solution Overview
Problem
Current sutures made from ultra-high molecular weight polyethylene (UHMWPE) and polyester fibers face challenges in evenly distributing strength and friction properties, particularly in orthopedic surgeries under high tension, such as ACL surgery, where achieving consistent performance is difficult due to uneven material distribution in braided filaments.
Innovation Solution
A braided filament is developed using strands with a specific combination of UHMWPE and polyester fibers, where each strand includes multiple fibers of varying weights, and a braiding machine is used to braid these strands together in a pattern that alternates the direction of the bobbins to create a homogeneous filament with improved strength and friction properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If UHMWPE fibers are used to provide strength properties, then the suture achieves high tensile strength, but the suture exhibits slippage due to low friction
Solution Approach 1:
The patent combines UHMWPE fibers (providing strength) with polyester fibers (providing friction) to create a composite filament. This composite structure allows the suture to simultaneously achieve high tensile strength from the UHMWPE component and adequate friction properties from the polyester component, resolving the contradiction between strength and slippage resistance
Solution Approach 2:
The patent creates strands with non-uniform fiber distribution where certain regions have different concentrations of UHMWPE and polyester fibers. This local variation in material composition allows different sections of the filament to exhibit different properties, with some areas optimized for strength and others for friction, thereby resolving the contradiction at a localized level
2Reliability
If individual strands are braided together to achieve both UHMWPE strength and polyester friction, then the suture gains combined properties, but the material distribution becomes uneven throughout the filament
Solution Approach 1:
The patent merges UHMWPE and polyester fibers at the strand level before braiding, creating composite strands where both fiber types are intermixed. This merging approach ensures that both materials are present throughout the entire filament structure, guaranteeing consistent performance properties along the length of the suture and eliminating the uneven distribution problem
Solution Approach 2:
The patent designs the filament structure to achieve homogeneous distribution of both UHMWPE and polyester materials throughout the entire braid. By carefully controlling the strand composition and braiding parameters, the patent ensures that every cross-section of the filament contains a consistent ratio of strength-providing and friction-providing materials, thereby achieving uniform performance characteristics
3Object-affected harmful factors
If monofilament strands are used, then the suture has smooth surface and reduced tissue drag, but the suture is stiff and difficult to tie
Solution Approach 1:
The patent uses composite multifilament strands combining different fiber types to achieve a balance between smoothness (low tissue drag) and flexibility (ease of knot-tying). The multifilament construction with varied fiber materials provides both the smooth surface characteristics needed for reduced tissue drag and the flexibility required for easy manipulation and knot-tying
Data Source
AI summary
In one embodiment, the present invention is a braided filament including a plurality of strands each having at least one ultrahigh molecular weight polyethylene fiber and at least one polyester fiber wherein the quantity of certain types of fibers in a first strand is the same as the quantity of the same type of fibers in a second strand. In a variant, one additional strand of the braided filament is a monofilament strand. In another variant, each strand is homogeneous with respect to the other strands and is made exclusively from ultrahigh molecular weight polyethylene fibers and polyester fibers such that each strand has the same distribution and quantity of fiber types.