Bone-Tendon-Bone Graft Cavities Prevent Tendon Slippage
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Solution Overview
Problem
Current bone-tendon-bone grafts face challenges in securely attaching slippery tendons to bone blocks, leading to slippage and loss of tension, which compromises the stability and healing of joint injuries, particularly in severe ligament damage cases.
Innovation Solution
The use of an intermediate bone block with strategically designed cavities, such as omega-shaped channels, on the tendon-engaging surface to enhance grip without damaging the tendon, allowing for full internal capture and even load distribution, thereby preventing slippage and improving tensile strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional bone-tendon-bone grafts are used with smooth bone surfaces, then the graft structure is simple, but the tendon slips and loses tension compromising stability
Solution Approach 1:
The invention applies local quality by creating cavities only on the tendon-engaging surface of the bone blocks, while keeping the rest of the bone block structure simple. The cavities are strategically positioned to receive and secure the tendon without compromising the overall structural integrity or increasing complexity elsewhere in the graft assembly.
Solution Approach 2:
The tendon is nested within the cavities of the bone blocks, with the soft tissue extending into the cavity spaces. This nesting arrangement provides secure retention of the tendon through the cavity geometry while maintaining a relatively simple overall graft structure that can be assembled from modular components.
2Reliability
If aggressive gripping methods are used to prevent slippage, then tendon capture is improved, but the tendon is damaged reducing tensile strength
Solution Approach 1:
The cavities serve as an intermediary structure between the bone block and the tendon. Rather than directly gripping or compressing the tendon with aggressive forces, the cavities provide a receiving space that gently secures the tendon through geometric fit, allowing the tendon to be captured without damage to its fibrous structure.
Solution Approach 2:
The invention changes the geometric parameters of the bone-tendon interface by introducing cavities with specific dimensions and shapes. These parameter changes create a retention mechanism that secures the tendon through shape complementarity rather than aggressive gripping, preserving the tendon's mechanical properties and tensile strength.
3Manufacturing precision
If bone-tendon-bone grafts are constructed with traditional methods, then surgical procedures are lengthy, but precise construction to predetermined gage length is difficult
Solution Approach 1:
The graft is segmented into modular components including bone blocks with integrated cavities and tendon portions. These segmented components can be pre-fabricated to precise dimensions and then assembled during surgery, allowing for accurate gage length construction while reducing the time required for intraoperative shaping and assembly.
Solution Approach 2:
The bone blocks are pre-formed with integrated cavities and precise dimensions before surgery. This preliminary preparation of the bone block geometry allows the graft to be constructed to predetermined gage lengths during surgery without requiring time-consuming shaping operations, thereby improving both precision and efficiency.
Data Source
AI summary
The present invention has multiple aspects. In its simplest aspect, the present invention is directed to an intermediate bone block comprising a machined segment of cortical bone, cancellous bone or both, the intermediate having a face comprising one to ten compression surfaces and one to ten cavities, the compression surfaces suitable for compressing soft tissue, the cavities for receiving and holding overflow soft tissue. The cavities are preferably channels, and more preferably channels having an omega cross-sectional profile. The invention is also directed to bone block assemblies suitable for binding to a soft tissue to form an implantable graft, and to such implantable grafts. A particularly preferred graft is a bone-tendon-bone graft.