Composite Suture Bridge Anchor for Bone Integration
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Solution Overview
Problem
Existing interference screws used in ligament reconstruction limit bone-to-ligament integration due to their size, which obstructs the surface area contact and leads to incomplete absorption, resulting in fibrous tissue formation instead of a well-ordered matrix, and often leave foreign material in the body.
Innovation Solution
A suture bridge anchor with a thicker distal end and open helical coil design that allows for greater suture load capacity and improved bone integration, combined with a delivery device that facilitates secure placement within bone tunnels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional interference screws are used to anchor the graft ligament, then the graft ligament is securely fixed in the bone tunnel, but the screw obstructs about 50% of the potential bone-to-ligament integration region, limiting surface area contact and resulting in incomplete absorption and fibrous tissue formation
Solution Approach 1:
The interference screw is segmented into multiple components including a threaded portion, a smooth portion, and a collar. The threaded portion engages the bone tunnel walls while the smooth portion allows graft passage, and the collar provides additional fixation. This segmentation reduces the obstructive volume while maintaining fixation security.
Solution Approach 2:
The interference screw incorporates a porous structure that allows bone ingrowth through the screw material itself. This porous architecture increases the effective bone-to-ligament integration surface area by enabling bone cells to penetrate and grow within the screw matrix, thereby reducing the obstructive effect while enhancing biological fixation.
2Duration of action of stationary object
If absorbable interference screws are used to allow complete absorption, then foreign material remains in the body for a shorter time, but the absorption process takes several months and the quality of bone-to-ligament in-growth is compromised with fibrous mass formation
Solution Approach 1:
The interference screw is constructed from composite materials combining bioabsorbable polymers with ceramic or metal reinforcements. The bioabsorbable portion gradually degrades over time while the reinforcing portion maintains structural integrity and promotes osteconduction. This composite structure enables complete absorption without compromising bone-to-ligament in-growth quality, as the ceramic or metal components serve as permanent scaffolds for bone formation.
3Strength
If the interference screw is made larger to provide adequate strength for advancement and holding, then mechanical strength is sufficient, but the screw occupies more space in the bone tunnel and further limits bone-to-ligament integration region
Solution Approach 1:
The interference screw utilizes composite materials with high strength-to-weight ratios, combining bioabsorbable polymers with ceramic or metal reinforcements. This allows the screw to maintain adequate mechanical strength for advancement and holding while reducing the overall volume and obstructive effect on the bone-to-ligament integration region.
Solution Approach 2:
The interference screw incorporates a porous structure that provides mechanical strength through the porous matrix architecture while reducing material density. The porous structure allows bone ingrowth, effectively increasing the functional surface area for bone-to-ligament integration without requiring a larger screw volume, thereby resolving the contradiction between strength and integration surface area.
Data Source
AI summary
The present disclosure relates to an anchor. The anchor includes a suture bridge having a proximal end and distal end. The distal end of the suture bridge has a thickness greater than a thickness of the proximal end of the suture bridge. At least two ribs extend from the proximal end of the suture bridge to a proximal end of the anchor. At least one open helical coil wraps around the at least two ribs and extends, substantially, from the proximal end of the suture bridge to the proximal end of the anchor. The at least one open helical coil defines an internal volume communicating with a region exterior to the anchor through apertures between turns of the at least one open helical coil. The at least two ribs are engagable with a grooved shaft of a driver.