Adjustable Graft Suspension Device for Ligament Fixation
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Solution Overview
Problem
Current graft fixation devices face challenges with rigid suture loops requiring multiple sizes, additional tunnel depth, and adjustable loops causing abrasion and potential lengthening issues during surgical procedures for ligament or tendon reconstruction.
Innovation Solution
A graft suspension device with an anchor, a ligament cradle, and an adjustable length of suture formed into loops, where the suture ends are threaded through apertures and joined to form a single tail, allowing loop size adjustment without cradle movement, preventing graft abrasion and maintaining centered positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rigid suture loops are used for graft fixation, then the graft can be securely fixed, but multiple sizes of loops are required and additional tunnel depth (3-5mm) is needed
Solution Approach 1:
The suture loop is made adjustable through a dynamic mechanism where the suture can be threaded through the cradle and anchor apertures, allowing the loop size to be changed by manipulating the free end of the suture. This eliminates the need for multiple rigid loop sizes while maintaining secure fixation.
2Adaptability or versatility
If adjustable suture loops are used to avoid multiple sizes, then loop size can be changed, but the cradle moves causing abrasion to the graft
Solution Approach 1:
The device is segmented into distinct functional components: the cradle with sleeve portion, the anchor with multiple apertures, and the suture. The cradle remains stationary while the suture loops are adjusted independently by threading the suture through the anchor apertures, separating the adjustment mechanism from the graft-contacting cradle.
3Adaptability or versatility
If adjustable suture loops are used, then loop size can be modified, but the loops may inadvertently lengthen after graft fixation
Solution Approach 1:
The suture is pre-configured with specific routing through the cradle sleeve and anchor apertures, creating a stable loop structure before graft fixation. The free end of the suture serves as a control mechanism that, when pulled, tensions the loops and prevents inadvertent lengthening after fixation.
4Adaptability or versatility
If the suture loop is made adjustable, then it can accommodate different bone tunnel sizes, but the complexity of the device increases
Solution Approach 1:
The anchor is designed with multiple apertures (outer pair, intermediate pair, and central pairs) that serve universal functions: the outer and intermediate apertures guide the suture for loop formation, while the central apertures allow the cradle to be positioned at different locations along the suture. This multi-aperture design provides a universal solution for different bone tunnel sizes without requiring multiple specialized devices.
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
A graft suspension device for suspending a ligament in a bone hole having a first loop and a second loop suspending from an 8-hole anchor, and a cradle at the opposite end of the loops to the anchor. The loose ends of the suture are routed through holes in the anchor separate from the loops and are joined together to form a single tail. A finger loop allows a surgeon to adjust the distance of the cradle from the anchor with the cradle staying centered with respect to the anchor as the distance is adjusted.