Adjustable Loop Length in Suspensory Graft Fixation
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Solution Overview
Problem
Existing suspensory graft fixation devices have fixed loop lengths, making them challenging to use in situations where the bone tunnel is too short for proper graft fixation, as they require a predetermined graft length for secure healing, and do not allow for adjustable loop lengths to accommodate varying tunnel and graft sizes.
Innovation Solution
A suspensory graft fixation device with an elongated anchor member and a filamentous loop that can be adjusted by pulling the suture ends in one direction to resize the loop and automatically lock it in place by applying tension in the opposite direction, ensuring secure fixation without requiring a predetermined graft length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed loop length is used in suspensory graft fixation devices, then the device structure is simple and easy to manufacture, but the device cannot accommodate varying tunnel and graft sizes, reducing adaptability
Solution Approach 1:
The patent applies the dynamics principle by making the suture loop length adjustable rather than fixed. The suture ends can be pulled to shorten the loop length, allowing the device to adapt to different bone tunnel sizes and graft lengths. This dynamic adjustment capability enables the same device to accommodate varying surgical requirements without requiring multiple fixed-size devices.
Solution Approach 2:
The patent implements parameter changes by allowing the loop length parameter to be modified during the surgical procedure. By pulling the suture ends, the loop length can be shortened from its initial state to match the specific bone tunnel dimensions. This parameter adjustment resolves the contradiction between having a simple fixed structure and achieving adaptability to various sizes.
2Reliability
If a predetermined graft length is required for secure healing, then graft fixation reliability is improved, but the device cannot be used in shorter bone tunnels, reducing versatility
Solution Approach 1:
The adjustable loop length allows the device to maintain reliable graft fixation in both standard and short bone tunnels. By dynamically shortening the loop to match the tunnel length, the device ensures adequate graft-tunnel contact for secure healing while expanding its applicability to shorter tunnels that would otherwise be incompatible with fixed-length devices.
Solution Approach 2:
The patent changes the loop length parameter to match the specific bone tunnel dimensions. In shorter tunnels, the loop is shortened by pulling the suture ends, ensuring the graft achieves proper fixation reliability without requiring a predetermined fixed graft length. This parameter adaptation enables reliable fixation across varying tunnel lengths.
3Adaptability or versatility
If excess space exists between the graft and tunnel wall, then the device can accommodate size variations, but fixation stability is reduced
Solution Approach 1:
The patent resolves this contradiction by allowing the loop length parameter to be adjusted to eliminate excess space. By shortening the loop through pulling the suture ends, the graft is positioned to maximize contact with the tunnel wall, ensuring fixation stability. The device maintains adaptability to size variations while achieving optimal stability by removing unnecessary gaps.
4Adaptability or versatility
If multiple fixed-size devices are produced to accommodate various graft and tunnel lengths, then adaptability is improved, but device complexity and inventory requirements increase
Solution Approach 1:
The patent applies the universality principle by designing a single device that can perform multiple functions across different size requirements. The adjustable loop length enables one device design to accommodate various graft and tunnel lengths, eliminating the need to produce and manage multiple fixed-size device variants. This universal design simplifies inventory requirements while maintaining full adaptability.
Solution Approach 2:
The dynamic adjustability of the loop length transforms a static multi-size device family into a single dynamic device. By allowing the loop length to be modified during use, the device achieves the functionality of multiple fixed-size devices without the complexity of producing and managing various size variants.
Data Source
AI summary
A suspensory fixation device has an elongated anchor member adapted to be transversely situated at the exit of a bone tunnel. A graft supporting loop member formed of a pair of parallel suture limbs extending from a bight portion is suspended transversely from the anchor member and has a loop length which is adjustable so the graft ligament can be supported in the bone tunnel at varying distances from the anchor member. When a graft ligament is attached to the saddle end of the loop member, the length may be shortened by pulling distally on the pair of limbs to pull the graft ligament into the bone tunnel. When tension is applied to the loop member by the graft pulling the loop proximally, the bight portion of the suture automatically locks the graft supporting loop member in place.