Knotless Bone Anchor with Pre-Formed Loops
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Solution Overview
Problem
Conventional bone anchors face challenges such as suture shearing, complex and difficult handling, and instability due to high tensile forces, especially in areas like the shoulder or knee, where knotting requires experience and can be unreliable, and the anchors may not be easily removable or flush with the bone.
Innovation Solution
A knotless bone anchor design with an expandable outer sleeve and an inner screw featuring a predetermined breaking point and square driving head, which limits torque to prevent over-driving and ensures smooth operation, along with a bio-absorbable material option, to provide a secure and removable fixation without knotting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional knotting techniques are used to attach suture to tissue, then the surgeon can secure the tissue to bone, but the procedure requires considerable experience and dexterity and knots may come undone or cause soft-tissue bridges
Solution Approach 1:
The invention extracts the knotting function from the surgical procedure by providing pre-formed loops on the anchor that eliminate the need for surgeon-knots. The suture is pre-configured with loops that automatically secure to tissue, removing the complex knot-tying step entirely while maintaining secure attachment.
Solution Approach 2:
The anchor with pre-formed loops provides self-service functionality where the loop structure automatically secures the suture to tissue without requiring surgical knotting. The design inherently performs the securing function through its geometry rather than requiring surgical skill to create secure connections.
2Reliability
If the anchor element is driven into the bone with projections to prevent removal, then the anchor provides stable fixation, but the anchor cannot be easily removed if false application occurs
Solution Approach 1:
The anchor employs dynamic engagement where projections engage bone tissue in a direction-dependent manner. The barbs or threaded features provide strong resistance to pull-out forces (stable fixation) but allow relatively easy insertion in the forward direction, enabling removal if needed by applying reverse forces that overcome the engagement in the opposite direction.
Solution Approach 2:
The anchor structure is segmented into functional zones: insertion surfaces designed for easy entry, engagement projections (barbs or threads) for stable fixation, and a distinct removal interface. This segmentation allows different portions of the anchor to serve opposing functions - strong holding in one direction while permitting controlled removal.
3Reliability
If the anchor element is designed with projections for secure fixation, then the anchor remains stable in bone, but the anchor may not be flush with the bone structure causing future irritation
Solution Approach 1:
The anchor features local quality differentiation where the distal end contains engagement projections (barbs or threads) for stable bone fixation, while the proximal end is designed to be flush or recessed relative to the bone surface. This spatial differentiation of properties allows simultaneous achievement of stable anchorage and absence of soft tissue irritation.
Solution Approach 2:
The anchor design transitions from radial engagement (projections extending outward for bone purchase) to axial positioning (proximal end flush with bone surface). By separating the fixation function (radial projections) from the surface profile (axial alignment), the design achieves stable fixation without protruding elements that would irritate surrounding tissues.
4Reliability
If the suture is threaded through the transverse bore and knotted externally, then the tissue can be secured to bone, but the knot is arranged on the outside of the operating site causing potential complications
Solution Approach 1:
The suture is pre-configured with loops formed before implantation. These pre-formed loops are positioned on the anchor such that when the suture is threaded through tissue and pulled, the loops automatically capture and secure the tissue without requiring external knotting. The securement action is built into the device structure in advance.
Solution Approach 2:
The invention extracts the knotting operation from the surgical procedure entirely. Instead of requiring the surgeon to tie knots externally to secure tissue, the pre-formed loop structure on the anchor provides automatic securement, removing the complex knot-tying step and its associated risks of coming undone or creating soft-tissue bridges.
Data Source
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AI summary
A suture anchor including a sleeve (1A, 1B) with an optional solid tip and a hollow interior portion. A transverse hole passes through a distal end of the sleeve. An inner screw (2) with a flat distal end and threads disposed on an outer surface and a driver head extension (3) monolithically connected with a proximal end of the inner screw (2) are also provided.