Sliding Knot Suture Loop for ACL Reconstruction Stability
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Solution Overview
Problem
Current cortical fixation devices (CFDs) for ACL reconstruction face challenges in maintaining graft-holding loop length stability under high cyclic loading, leading to potential clinical failure due to stretching, especially with adjustable-length CFDs that require precise tunnel drilling and can cause tunnel widening or breaching.
Innovation Solution
A medical implant featuring a cortical fixation device with a sliding knot mechanism that allows for adjustable loop lengths without the need for additional knots, utilizing a twisted and non-twisted loop configuration with a suture thread system that includes a self-tightening sliding knot and a second suture thread for loosening, embedded in a slot with friction-enhancing teeth for secure fixation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If adjustable-length CFDs are used to accommodate varying tunnel lengths, then adaptability to different surgical conditions is improved, but the risk of loop lengthening under cyclic loading increases leading to clinical failure
Solution Approach 1:
The suture loop system incorporates a sliding knot mechanism that allows dynamic adjustment of loop length during surgery while maintaining a fixed, stable configuration during loading. The sliding knot can move along the suture thread to adjust length, but once positioned, it prevents further lengthening under cyclic loading through its friction-based locking mechanism.
Solution Approach 2:
The invention changes the physical state of the suture loop from adjustable to fixed by using a sliding knot that transitions from a movable state (during surgery for length adjustment) to a locked state (during loading where it prevents further lengthening). This parameter change ensures the loop maintains its set length under cyclic loading.
2Strength
If traditional knot-tying methods are used to secure the suture loop, then fixation strength is improved, but surgical time and complexity increase
Solution Approach 1:
The invention extracts the time-consuming knot-tying step from the surgical procedure by replacing it with a sliding knot mechanism. The sliding knot is pre-formed on the suture thread and can be simply positioned and locked along the loop, eliminating the need for surgeons to perform complex knot-tying maneuvers during surgery.
Solution Approach 2:
The sliding knot mechanism is self-securing through its friction-based design. Once the sliding knot is positioned at the desired location on the suture thread, it automatically locks in place through friction between the knot and the suture material, without requiring additional tying steps or tools from the surgeon.
3Reliability
If adjustable-length CFDs with short continuous loops are used, then fixation security is improved, but the risk of tunnel widening or breaching the lateral femoral wall increases
Solution Approach 1:
The sliding knot mechanism allows the suture loop to be dynamically adjusted to the optimal length during surgery, then locked in place. This enables the use of shorter loops for secure fixation without the risk of excessive tension causing tunnel widening or femoral wall breaching, as the loop length can be precisely controlled and maintained.
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
The solution provides a secure, adjustable, and knot-free fixation of ligament or tendon grafts, reducing the risk of clinical failure by preventing excessive loop elongation and allowing easy re-adjustment of loop lengths, thus enhancing the stability and effectiveness of ACL reconstruction.
Implementation Method 1
a sliding knot on the rear side of the body, and wherein the medical implant comprises a second suture thread extending through the sliding knot
Implementation Method 2
a first suture thread extending through said through-holes and forming a twisted loop and a non-twisted loop on the first side of the body
Data Source
AI summary
The invention relates to a medical implant (1), comprising at least a first cortical fixation device (200) for fixing a ligament or tendon graft (G) in a desired position, wherein said first cortical fixation device (200) comprises a body (201) having a front side (201a) and a rear side (201b), which rear side (201b) faces away from the front side (201a), and wherein said body (201) comprises a first and an adjacent second through-hole (210, 211), which through-holes (210, 211) extend from the front side (201a) to the rear side (201b) of said body. According to the invention the medical implant (1) further comprises a first suture thread (100) extending through the through-holes (210, 211) and forming a twisted loop (104) and a non-twisted loop (105) on the front side (201a) of the body (201), and a sliding knot (108) on the rear side (201b) of the body (201), and wherein the medical implant (1) comprises a second suture thread (300) extending through the sliding knot (108).