Adjustable Textile Loop-Band Fixation for Low-Wear Bone Tunnels
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Solution Overview
Problem
Existing suspension fixation devices for ligament repair, such as those using titanium plates and suture coils, suffer from instability due to material stiffness differences, leading to wear, fixation failures, and bone damage, and require complex pre-surgical measurements and knotting processes.
Innovation Solution
An adjustable and fully flexible loop-band fixation device made of flexible woven textile material, featuring a fixation band with a tightening loop and adjustable coil, which includes a self-locking knot to provide stable, adjustable fixation without the need for additional knotting or screw implantation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If metal material (titanium plate) is used in fixation device, then structural stability is improved, but wear and stress concentration occur due to stiffness difference with suture material
Solution Approach 1:
The invention changes the material parameter from rigid metal to flexible woven textile material with elastic modulus of 100-500 MPa, matching the physiological elastic modulus of ligaments. This parameter change eliminates the stiffness mismatch that causes wear and stress concentration, while maintaining structural stability through the unique interlaced loop structure that provides progressive resistance.
Solution Approach 2:
The invention uses composite structure combining flexible woven textile material with specific interlaced loop configuration. The composite of material and structure creates a fixation device that exhibits both flexibility for biocompatibility and structural stability for fixation, eliminating the need for metal-suture combinations that cause wear.
2Strength
If metal material is used in fixation device, then fixation strength is improved, but bone damage occurs due to hard-on-hard contact and drilling
Solution Approach 1:
The invention changes the material hardness parameter by using flexible woven textile material with elastic modulus of 100-500 MPa, which is significantly softer than metal. This allows the fixation device to pass through bone tunnels with minimal drilling and avoids hard-on-hard contact that causes bone damage, while maintaining fixation strength through the loop structure's mechanical interlocking.
3Device complexity
If non-adjustable length band is used, then device simplicity is improved, but surgical efficiency decreases due to need for measurement and calculation
Solution Approach 1:
The invention introduces a sliding knot mechanism that allows the band length to be dynamically adjusted during surgery. The sliding knot can be moved along the band to change the loop size, eliminating the need for pre-surgical measurement and calculation. This dynamic adjustment capability simplifies the device while significantly improving surgical efficiency.
4Adaptability or versatility
If adjustable length band with additional fixation is used, then adaptability is improved, but device complexity increases due to additional screws and knotting
Solution Approach 1:
The invention uses a self-locking sliding knot mechanism that automatically maintains the adjusted length without requiring additional screws or complex fixation. The sliding knot self-locks at the desired position through friction and geometry, providing adaptability while keeping the device structure simple and avoiding additional fixation components.
5Object-affected harmful factors
If folded and contracted thread band structure is used, then flexibility is improved, but fixation reliability decreases due to unbalanced stress causing pulling into bone tunnel
Solution Approach 1:
The invention segments the band into multiple loops formed by repeated interlacing of the pull suture through the fixation band. This segmentation creates multiple load-bearing points that distribute stress evenly, preventing unbalanced stress that would cause the folded band to pull into the bone tunnel. The segmented loop structure maintains flexibility while ensuring fixation reliability.
Solution Approach 2:
Instead of folding and contracting the thread band in a way that creates unbalanced stress, the invention inverts the approach by using repeated interlacing to form loops that distribute stress evenly. The pull suture interlaces through the band multiple times to create a structure where stress is balanced across all segments, preventing the band from being pulled into the bone tunnel.
Data Source
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AI summary
The present application relates to an adjustable and fully flexible loop-band fixation device including a fixation band, a fixation loop, and a traction thread which are all made of flexible woven textile material. A wound tightening structure formed by interlacing of a pull suture in the middle and two sides of the fixation band fits an 8-shaped adjustable coil formed by extending on a side of the fixation band; and the 8-shaped adjustable coil has an anti-reverse structure and a self-interlacing structure, which form the fixation loop as a whole.