Composite Interference Screws with Segmented Runners for Bone Tunnel Integration
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Solution Overview
Problem
Existing interference screws used in ligament reconstruction procedures occupy significant space within bone tunnels, limiting bone-to-ligament integration and causing incomplete absorption, leading to foreign material retention in the body.
Innovation Solution
A delivery device and screw combination featuring a non-circular cannulation, open helical threads, and a suture bridge with runners, allowing for improved positioning and absorption of the interference screw, promoting better bone-to-ligament integration and reducing foreign material retention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a traditional interference screw is used to anchor the graft ligament, then the graft ligament is securely fixed in the bone tunnel, but the screw occupies significant space within the bone tunnel, limiting bone-to-ligament integration
Solution Approach 1:
The interference screw is divided into multiple longitudinal segments or struts that are separated by spaces, allowing bone tissue to grow through and around the screw structure, thereby reducing overall screw occupancy volume while maintaining fixation strength through distributed anchoring points
Solution Approach 2:
The interference screw is designed with a porous or lattice-like internal structure that allows bone ingrowth through the screw body, reducing the effective occupancy volume and promoting bone-to-ligament integration while maintaining mechanical strength through the porous framework
2Loss of substance
If an absorbable interference screw is used, then the foreign material retention is reduced over time, but the absorption process is incomplete, leading to foreign material retention in the body
Solution Approach 1:
The screw is designed with varying material composition parameters along its length or structure, with different sections having different absorption rates, allowing for complete degradation over time while maintaining initial mechanical strength, ultimately achieving complete absorption without foreign material retention
Solution Approach 2:
The interference screw is constructed from composite materials that combine biodegradable polymers with different absorption characteristics, enabling controlled and complete absorption over time, with the composite structure ensuring both initial strength and complete degradation without permanent foreign material retention
Data Source
AI summary
The present disclosure relates to a delivery device and screw combination. The combination includes a delivery device comprising a handle and a shaft coupled to the handle, the shaft including a proximal end, a distal end, a non-circular cannulation, and markings along a length of the shaft; an interference screw coupled to the delivery device comprising a proximal end and a distal end, the screw including threads extending in an open helical form from the proximal end to the distal end, a suture bridge located at a distal end of the screw and housed within a slot of the delivery device shaft, and a plurality of runners extending longitudinally along an interior of the screw, the runners housed within grooves of the delivery device shaft; and a suture disposed around the suture bridge, ends of the suture extending through the cannulation of the delivery device shaft.