Flexible Wire Ligament Fixation via Blocking Screw
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for fixing short ligament grafts in bone tissue face challenges such as increased elasticity and mechanical instability due to the use of synthetic relays, which can lead to graft loosening and widening of bone tunnels, and require additional steps like creating specific bone compartments, compromising the minimally invasive nature of the procedure, especially in smaller anatomical structures like children's bones.
Innovation Solution
A system using a solid wire with fixed corpuscles and a blocking screw that neutralizes the elasticity of the suspension wire by interacting with the corpuscles within the bone tunnel, allowing for independent positioning and tensioning of the graft before locking, and eliminating the need for a specific bone compartment, thus providing a more stable and minimally invasive fixation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If synthetic relays are used to connect the graft to the fixation organ, then the graft can be anchored at the cortical bone level with high tensile strength, but the elasticity of the synthetic relay increases proportionally to its length, which negatively affects the mechanical properties of the system
Solution Approach 1:
The patent introduces a blocking member as an intermediary element that directly contacts and blocks the suspension wire within the bone tunnel, eliminating the need for long synthetic relays. The blocking member acts as a mediator between the wire and the bone tunnel wall, providing mechanical stability without the elastic properties of synthetic materials.
Solution Approach 2:
The patent extracts the problematic elastic synthetic relay from the system by directly anchoring the fixation organ at the cortical bone level and using a blocking member to secure the suspension wire within the tunnel, thereby eliminating the source of elasticity and micro-movements.
2Reliability
If the fixation organ is anchored close to the graft to minimize synthetic relay length, then the elasticity is reduced, but this requires creating a specific bone compartment to accommodate the fixation organ, which compromises the minimally invasive nature of the procedure
Solution Approach 1:
The patent removes the need for a specific bone compartment by using a blocking member that fits within the existing bone tunnel geometry. The blocking member is designed to be accommodated within the natural confines of the bone tunnel without requiring additional preparatory steps.
Solution Approach 2:
The blocking member is designed with specific local geometric properties (shape, size, surface features) that allow it to interact with the suspension wire and bone tunnel wall in a localized manner, providing stable fixation without requiring modification of the overall bone tunnel structure.
3Ease of operation
If a blocking member is introduced into the bone tunnel to lock the suspension wire, then the wire positioning and tensioning can be adjusted independently before locking, but the blocking member must interact with the wire corpuscles to prevent slippage
Solution Approach 1:
The suspension wire is segmented with discrete corpuscles along its length, allowing the blocking member to engage with specific corpuscles at different positions. This segmentation enables independent adjustment of wire positioning and tensioning before final locking, as the blocking member can interact with different corpuscles during the adjustment process.
Solution Approach 2:
The corpuscles act as intermediary elements between the suspension wire and the blocking member. These discrete structures provide a mechanical interface that allows the blocking member to securely engage the wire without direct contact between the smooth wire surface and the blocking member, preventing slippage while allowing adjustment.
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
This solution enables secure fixation of ligament grafts through bone tunnels of reduced diameter without a specific compartment, maintaining mechanical stability and minimizing tissue damage, while allowing for adjustable tension and preventing graft loosening, thus improving the efficacy of ligament reconstruction.
Implementation Method 1
a blocking screw introduced into the same bone tunnel parallel to the wire and blocking it by interacting with said corpuscles
Implementation Method 2
these corpuscles being able to interact with the relief of a blocking member introduced into the same bone tunnel
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention concerns a device for attaching soft tissue to bone tissue, e.g. a broken ligament or ligament graft (1), comprising a flexible wire (10) provided with several corpuscles (9, 9', 9") fixed along the length of same, and a screw (8) capable of engaging with said corpuscles of the wire (10) when screwed into a bone tunnel (4) by blocking them between the screw pitch and the bone tissue. The wire is capable of forming a free loop (2) for receiving said soft tissue, e.g. a ligament graft, the two branches of said loop being provided with said corpuscles. The wire can also be provided with a closed loop or a crimped needle. The screw is a cannulated screw for receiving a guide pin (6).