One-Way Adjustable Loop Suture Construct for Secure Graft Fixation
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Solution Overview
Problem
Existing devices and methods for securing soft tissue to bone, such as ligament grafts, lack sufficient strength and adjustability, often leading to loosening or migration of the grafts due to the use of knots and limited geometry, which can result in reduced fixation strength and increased trauma to surrounding tissue.
Innovation Solution
A suture construct with a one-way adjustable loop formed from a single suture filament, featuring two interconnected loops and constricting tails that prevent expansion, allowing for secure positioning and adjustment of the graft without the need for splices or multiple knots, thereby enhancing strength and versatility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If knots are used to maintain the location of the suture loop with respect to the cortical button, then the graft can be positioned at the desired location during the procedure, but the knots can loosen or slip post-operatively, causing the loop circumference to increase and the graft to move away from the desired location
Solution Approach 1:
The patent replaces the traditional knot-based mechanical system with a one-way adjustable loop system that uses a cortical button with a loop configuration and suture arrangement to achieve positioning without requiring knots. The loop can be adjusted during surgery and then locked in place, eliminating the loosening problem associated with knots while maintaining positioning precision.
Solution Approach 2:
The suture construct incorporates dynamic adjustment capability through the one-way adjustable loop, allowing the surgeon to tighten or loosen the suture during the procedure to achieve precise graft positioning, and then the loop locks to maintain that position permanently, providing both adjustability and reliability.
2Reliability
If multiple knots are used to secure the suture loop, then the graft can be maintained at the desired location, but the additional surface area of the knots increases the risk of trauma to surrounding tissue
Solution Approach 1:
The patent eliminates knots entirely by using a cortical button with an integrated loop system and suture arrangement that achieves secure fixation without requiring knotted connections. This substitution removes the source of tissue trauma associated with knot surface area while maintaining fixation reliability through the button's geometric engagement with the bone tunnel and soft tissue.
3Device complexity
If traditional suture constructs are used without adjustability, then the procedure is simpler, but it is difficult to control placement of multiple ligament grafts without also moving other ligament grafts
Solution Approach 1:
The one-way adjustable loop provides dynamic adjustment capability that allows independent control of each graft's tension and position. The loop can be tightened or loosened independently for each graft during the procedure, enabling precise control over multiple ligament graft placements without affecting other grafts, while the locked configuration maintains stability after adjustment.
Solution Approach 2:
The suture construct is segmented into independent adjustable components, with each cortical button and its associated loop forming an independently controllable unit. This segmentation allows each graft to be adjusted and secured independently, providing fine control over individual graft placement while maintaining overall procedural simplicity through standardized components.
4Adaptability or versatility
If splices are used as one-way fixation elements, then adjustability can be achieved, but a longer length of the loop is required to achieve security, thereby increasing the minimum adjustable length
Solution Approach 1:
The patent transitions from linear adjustment mechanisms like splices to a two-dimensional loop configuration around the cortical button. The loop wraps around the button's external surface, utilizing the button's geometry to provide mechanical advantage and locking action. This dimensional change allows for secure fixation with a shorter loop length, as the loop engages the button's width and thickness rather than relying solely on linear suture length.
Data Source
Figure 1
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Figure 4A~4B
AI summary
Disclosed are surgical constructs and methods of use for a one-way adjustable fixation loop that is formed by tying two knots in a surgical filament, each knot defining an individual adjustable loop and the individual adjustable loops being interconnected to form the one-way adjustable fixation loop. The knots enable a non-spliceable suture to be used in the creation of the one-way adjustable fixable loop. Embodiments can include a fixation device, such as a cortical button or plate for use in a bone tunnel, and enable the knots to work independent of and suspended below the fixation device. Embodiments can increase the compatibility of the adjustable fixation loop with existing fixation devices and can isolate and protect the knots from damage during use and after implantation.