Prosthetic Ligament Guide Element Jamming Prevention
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Solution Overview
Problem
Prior prosthetic ligament implantation techniques face difficulties due to the potential for guide elements to jam in bone tunnels, requiring greater force and risking breakage, especially when the flipping suture becomes tense or entangled, which can delay or jeopardize surgery if replacement sutures are not available.
Innovation Solution
An implantation assembly featuring a guide element with a pulling loop and a manipulating loop, where the pulling loop is configured to prevent tensile load in the manipulating loop during passage through bone tunnels, ensuring the guide element remains in the pulling position until cleared of the tunnel exit, and then manipulated to an anchoring position without causing jamming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the flipping suture is used to manipulate the guide element during pulling, then the guide element can be positioned to overlie the tunnel mouth, but the flipping suture may become tense or entangled causing the guide element to jam in the tunnel
Solution Approach 1:
The manipulation function is segmented from the pulling function by providing separate manipulation apertures and manipulating elements. The guide element includes multiple apertures: pulling apertures for pulling elements and manipulating apertures for manipulating elements. This segmentation allows independent control of pulling and manipulation operations, preventing interference between the two functions that causes jamming.
Solution Approach 2:
The manipulation function is extracted from the pulling operation. The manipulating elements are separate from the pulling elements and act through distinct manipulating apertures. This extraction ensures that manipulation forces are applied independently without affecting the pulling suture tension, eliminating the risk of entanglement-induced jamming.
2Productivity
If greater force is applied to pull the guide element through the tunnel when jamming occurs, then the guide element can be pulled through, but the pulling suture may break
Solution Approach 1:
The system segments the forces applied to the guide element by providing separate pulling and manipulating elements. The manipulating elements apply lateral forces through manipulating apertures to reposition the guide element without requiring increased pulling force. This prevents the need to exceed the pulling suture's strength limit when resolving jamming conditions.
Solution Approach 2:
The manipulating elements act as intermediaries to resolve jamming by applying lateral manipulation forces through manipulating apertures. Instead of directly increasing pulling force on the vulnerable pulling suture, the manipulating elements mediate the repositioning process, allowing the guide element to be freed from jamming without subjecting the pulling suture to excessive tensile loads.
3Reliability
If replacement pulling suture is not available in the operating room, then the surgery may be delayed or cancelled, but having multiple sutures increases device complexity
Solution Approach 1:
The guide element is designed with multi-functionality, incorporating both pulling apertures and manipulating apertures in a single device. This universal design allows the same guide element to respond to both pulling forces and manipulation forces, providing operational flexibility without requiring multiple separate components or replacement sutures, thereby maintaining surgery continuity without proportionally increasing complexity.
Solution Approach 2:
The guide element is pre-configured with multiple apertures for both pulling and manipulating functions before implantation. This preliminary preparation ensures that manipulation capabilities are already integrated into the device structure, eliminating the need for complex intraoperative assembly or replacement of components and ensuring surgical continuity.
Data Source
AI summary
An implantation assembly (16) has a guide element (22) for a ligament (18); a pulling element (24) comprising a pulling loop (26); and a manipulating loop (28). The guide element has a pulling aperture (36) towards a leading end (32), a manipulating aperture (38) towards a trailing end (34), and a connecting arrangement (40) for the ligament. The pulling and manipulating loops pass through the respective apertures. When the guide element emerges from a bone tunnel mouth, the manipulating loop is used to manipulate the guide element to a position where it overlies the tunnel mouth. The manipulating loop is secured to the pulling element and arranged such that a tensile load can be applied to the pulling element without generating a tensile load in the manipulating loop which could otherwise cause the guide element to be manipulated towards the anchoring position during passage along the bone tunnels.