Trephine System for Ligament Reconstruction with Sliding Support Stem
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Solution Overview
Problem
Current methods for reconstructing ligaments, such as ACL reconstruction, face challenges with interference screws that occupy significant space in bone tunnels, limiting bone-to-ligament integration and requiring additional procedural steps and devices for accurate trephine core harvesting.
Innovation Solution
A trephine system comprising an adaptor, a reamer, and a reamer support stem that allows for concentric mounting and sliding movement, enabling direct engagement with a guide wire for bone tunnel formation and harvesting without additional guides, along with compaction pliers for shaping bone plugs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If interference screws are used to secure the graft ligament in the bone tunnel, then the graft ligament is firmly anchored, but the interference screw occupies significant space within the bone tunnel, limiting the bone-to-ligament integration region
Solution Approach 1:
The patent removes the interference screw from the bone tunnel entirely, replacing it with a guide wire that passes through the tunnel. The graft ligament is secured using buttons or loops that engage with the guide wire from the outside, eliminating the space-occupying screw while maintaining anchoring strength and maximizing bone-to-ligament contact area.
2Measurement precision
If additional guides are used for accurate trephine core harvesting, then the accuracy of bone tunnel formation is improved, but the number of devices and procedural steps increases
Solution Approach 1:
The guide wire serves multiple functions: it acts as a positioning guide for trephine core harvesting, defines the bone tunnel path, and serves as the anchoring mechanism for the graft ligament. This multi-functionality eliminates the need for separate guiding devices while maintaining high accuracy in bone tunnel formation.
3Object-generated harmful factors
If bioabsorbable interference screws are used, then the foreign material is eventually absorbed, but the absorption process takes substantial time (around three years) and the quality of bone-to-ligament in-growth is different from natural in-growth
Solution Approach 1:
The patent extracts the bioabsorbable screw from the system, replacing it with a permanent guide wire and external buttons/loops. This eliminates the prolonged foreign material presence and associated delays in natural bone-to-ligament in-growth, allowing immediate and natural integration without the three-year absorption period.
Data Source
AI summary
The present invention relates to medical apparatuses and procedures for reconstructing a ligament. There is provided a trephine (10) comprising an adaptor (11), an elongate reamer (12) coupled thereto, and a reamer support stem (13), wherein the reamer support stem is mounted concentrically within the reamer and adaptor, and wherein at least a portion of the reamer support stem is slidably moveable about a longitudinal axis of the trephine.