Variable Density Soft Anchor Sheath for Bone Fixation
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Solution Overview
Problem
Existing surgical suture constructs lack the ability to provide a knotless, self-tensioning, and self-locking repair with consistent fixation and tissue compression, particularly in soft tissue to bone fixation.
Innovation Solution
A soft anchor sheath with varying densities along its length, featuring a non-regular braid, weave, or knit density pattern, which allows for deformation and anchoring in bone in different ways, providing a knotless, self-tensioning, and self-locking repair.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a uniform density soft anchor sheath is used, then the manufacturing process is simple, but the anchoring consistency and fixation reliability are poor
Solution Approach 1:
The soft anchor sheath incorporates varying braid densities at different locations along its length. Specifically, the sheath has a first braid density in a first portion and a second braid density in a second portion, where the densities differ. This local variation in structural quality enables different deformation characteristics in different regions, improving anchoring consistency within bone tunnels while maintaining overall device functionality.
Solution Approach 2:
The sheath is divided into distinct segments with different braid densities. The first portion and second portion are treated as separate functional segments, each with optimized density characteristics for their specific roles during anchoring and tissue fixation. This segmentation allows each portion to perform its function optimally without compromising the other.
2Ease of operation
If a knotless surgical construct is used, then the surgical procedure is simplified with fewer passing steps, but the self-tensioning and self-locking capability must be achieved through alternative mechanisms
Solution Approach 1:
The soft anchor sheath is designed to automatically set and lock within the bone tunnel through its own deformation characteristics. The varying braid densities enable the sheath to bunch and deform in specific patterns when tension is applied, creating a self-locking mechanism that secures the construct without requiring external knots or additional components. The sheath serves its own anchoring function through its engineered density variations.
Solution Approach 2:
The construct utilizes changes in the physical state and deformation parameters of the soft anchor sheath to achieve self-tensioning and self-locking. When tension is applied during surgery, the sheath transitions from its initial configuration to a deformed state where the varying density portions bunch at different rates, creating mechanical interlocking within the bone tunnel. This parameter change from undeformed to deformed state provides the self-locking mechanism.
3Reliability
If the soft anchor sheath deforms uniformly, then the deformation process is predictable, but the anchoring reproducibility and tissue compression are insufficient
Solution Approach 1:
The sheath incorporates specific local density variations with defined first and second braid densities in different portions. This controlled local quality variation ensures that when deformation occurs, specific portions bunch in a predictable and reproducible manner within the bone tunnel, enhancing anchoring consistency while maintaining manufacturability through defined density patterns.
Data Source
AI summary
Surgical anchor constructs, fixation devices, and methods of manufacturing, as well as methods for tissue repairs are disclosed. A soft suture anchor has a sheath with varying densities along the length of the sheath. The anchor sheath can have different segments with different densities which can be provided in a pattern or a random manner. The segments with different densities allow secure fixation of the soft anchor within bone, and attachment of first tissue to second tissue.