Adjustable Graft Fixation Sleeve for Bone Tunnel Positioning
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Solution Overview
Problem
Existing implantable fastening devices for securing grafts to bones in joints, such as the knee, lack the ability to adjust the graft's position within bone canals without new surgery and fail to maintain proper tension, leading to potential damage and instability post-operatively.
Innovation Solution
A hollow tubular elongate textile element with adjustable loops that can be compressed or extended to secure and adjust the graft's position within bone canals, using a bearing element with through openings to minimize friction and allow for reversible fixation without damaging the graft or bone.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the graft is fastened using interference screws or blocking screws in tunnels, then the graft is secured to the bone, but the position of the graft cannot be adjusted after implantation without new surgery
Solution Approach 1:
The device transforms a static fixation system into a dynamic one by incorporating a movable elongate element that can slide within the hollow tubular element. This allows the graft position to be adjusted post-implantation by pulling the elongate element, while maintaining secure fixation through friction between the elongate element and the tubular element walls.
Solution Approach 2:
The hollow tubular element acts as an intermediary between the bone tunnel and the graft, providing a controlled environment for the elongate element to slide within. This intermediary structure enables position adjustment while maintaining secure graft fixation through the friction interface.
2Adaptability or versatility
If the elongate element is passed through bone canals to adjust graft position, then the graft position can be modified, but the free end may abrade and damage the graft or modify its position unintentionally
Solution Approach 1:
The hollow tubular element serves as a protective intermediary that guides the elongate element through the bone canal. This tubular protection prevents the elongate element from directly contacting and abrading the graft, while still allowing position adjustment by pulling the elongate element through the protected pathway.
Solution Approach 2:
The hollow tubular element acts as a flexible protective sheath that encloses the elongate element during its movement through the bone canal. This shell structure prevents direct contact between the elongate element and surrounding tissues, reducing abrasion risks to the graft.
3Reliability
If traditional fastening devices are used, then the graft is secured firmly, but the device complexity increases and requires new surgery for any position adjustment
Solution Approach 1:
The device merges the fixation function and the adjustment function into a single integrated structure. The hollow tubular element and elongate element work together to provide both secure graft fixation through friction and the capability for post-implantation position adjustment, eliminating the need for separate adjustment mechanisms or additional surgery.
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 adjustable and secure fixation of grafts within bone canals, maintaining tension and stability without new surgery, while minimizing tissue and bone damage, and allowing for reversible positioning to ensure proper graft placement and mechanical integrity.
Implementation Method 1
traction exerted on the first free end causes the admission and exit orifices to move towards each other and correspondingly causes the sleeve to expand radially
Implementation Method 2
traction exerted on the first free end generates friction between the outer surface of the elongate element and the inner surface of the sleeve, thereby causing it to be compressed radially
Data Source
AI summary
The present disclosure provides an implantable fastening device for securing a graft to at least one bone of a joint, comprising a hollow tubular elongate textile element defining an inside volume and including a first free end and a second free end; and a bearing element having at least two through openings. Said elongate element has an initial outside diameter d0 (mm) and includes an admission orifice leading into its inside volume and an exit orifice going from its inside volume that are spaced apart by an initial distance m0 (mm) defining a sleeve, the first end of said elongate element being passed into the sleeve so as to form a first loop with at least a portion thereof being passed through at least two through openings of said bearing element. The second free end of said elongate element forms a second loop passing through a through opening of said bearing element. The sleeve receiving a portion of elongate element has an outside diameter at rest n0, and the distance m0 and the outside diameter d0 of said elongate element are determined in such a manner that in operation, traction exerted on the first free end causes the admission and exit orifices to move towards each other and correspondingly causes the sleeve to expand radially.