Single Graft Double Bundle ACL Reconstruction with Adjustable Fixation
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Solution Overview
Problem
Double-bundle ACL and PCL reconstructions face challenges in finding enough autograft tissue and require additional fixation devices that are difficult to use, especially since existing devices fail to allow individual tensioning of bundles and often need intraarticular positioning.
Innovation Solution
A graft construct secured in three tunnels with individual tensioning, using a single double-bundle construct with three adjustable button/loop constructs that eliminate the need for additional fixation devices, allowing for anatomically correct ligament reconstruction without intraarticular tensioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If double-bundle ACL and PCL reconstructions are performed with two separate grafts, then individual tensioning of bundles is achieved, but graft tissue availability is insufficient and morbidity increases
Solution Approach 1:
The single graft is divided into two separate bundles (AM and PL bundles) that can be individually tensioned and fixed in separate tunnels. The graft construct includes first and second bundles that are secured independently, allowing individual tensioning while using a single source of graft tissue.
Solution Approach 2:
Two separate grafts are merged into a single graft construct that provides both AM and PL bundle functionality. The single graft is configured to create two distinct bundles that can be fixed independently, combining the advantages of double-bundle reconstruction with the benefits of single-graft harvesting.
2Quantity of substance
If devices that split a single graft into two bundles are used, then graft tissue availability is improved, but individual tensioning is not allowed and device complexity increases
Solution Approach 1:
The single graft is segmented into two distinct bundles (AM and PL) that can be individually tensioned. Each bundle is secured in a separate tunnel with independent fixation, allowing individual tensioning control while maintaining the benefit of using a single graft source.
Solution Approach 2:
The fixation devices include adjustable components that allow dynamic tensioning of each bundle independently. The construct enables separate adjustment of AM and PL bundle tensions to achieve optimal ligament reconstruction.
3Reliability
If additional fixation devices are used to secure bundles in tunnels, then fixation reliability is improved, but device complexity and difficulty of use increase
Solution Approach 1:
Multiple fixation functions are merged into a simplified construct where the single graft with its two bundles is secured using coordinated fixation in separate tunnels. The AM and PL bundles are fixed independently, providing reliable fixation without requiring complex additional devices.
Solution Approach 2:
The fixation system uses universal button/loop constructs that can be applied to both AM and PL bundles, providing consistent and reliable fixation across different bundle locations without requiring specialized devices for each bundle.
4Manufacturing precision
If intraarticular positioning of fixation devices is required, then fixation precision is improved, but ease of operation deteriorates
Solution Approach 1:
Instead of requiring intraarticular positioning of fixation devices, the construct is designed to be fixed from extraarticular access. The AM and PL bundles are secured in their respective tunnels using approaches that avoid the need for instruments to be positioned inside the joint, reversing the traditional approach.
Solution Approach 2:
The fixation is segmented into separate tunnel entries that can be accessed independently from extraarticular portals. This segmentation allows precise positioning of each bundle in its respective tunnel without requiring intraarticular manipulation.
Data Source
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AI summary
A double bundle graft construct for fixation of bone to bone, or soft tissue to bone, that requires only three bone tunnels and a single graft and allows individual tensioning of the graft in each of the three tunnels. More specifically, the double bundle graft construct is formed of a single tissue loop and three fixation devices, such as adjustable button/loop constructs, attached to the single tissue loop. The adjustable button/loops of the double bundle graft construct allows individual tensioning of each of the bundles (e.g., tensioning of each of the anteromedial (AM) and posterolateral (PL) bundles of the ACL) and eliminate the need for additional fixation devices (for example, interference screws) to secure the bundles within the bone tunnels/sockets.