Radiolucent Bone Fusion Block for Joint Arthrodesis
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Solution Overview
Problem
Current methods for fusing bones in joints, such as arthrodesis and open-wedge osteotomies, face challenges like difficulty in achieving end-to-end contact, hardware failure, and inadequate bone integration, leading to complications like iatrogenic deformity and non-unions, especially in small joints like the foot and wrist.
Innovation Solution
A bone fusion system comprising hollow tubular fusion blocks and plates that securely hold bone graft material between bones, allowing for precise alignment and stabilization, reducing the need for extensive dissection and minimizing vascular compromise, while being adaptable to various joint shapes and sizes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If resectional arthrodesis is performed without interpositional bone grafting, then the procedure is simpler, but the fusion area becomes shorter resulting in iatrogenic deformity
Solution Approach 1:
The patent introduces an interpositional bone graft as a mediator between the resected bone ends. This graft maintains the desired correction and fusion area length while allowing the arthrodesis procedure to proceed. The bone graft acts as a spacer that prevents iatrogenic deformity by preserving the appropriate fusion area length.
2Measurement precision
If high-angle interfragmentary screws are used to bring bones together, then bone alignment is achieved, but screw pull-out and unintended bone fracture occur
Solution Approach 1:
The patent performs preliminary bone grafting to establish a stable foundation before inserting fixation hardware. The bone graft is placed and allowed to begin integration prior to final hardware insertion, creating a more reliable base that reduces the risk of screw pull-out and bone fracture during and after the procedure.
Solution Approach 2:
The bone graft serves as an intermediary that facilitates bone union and provides a stable foundation for hardware fixation. By introducing this intermediate element, the patent reduces the mechanical stress on the fixation screws, thereby preventing screw pull-out and unintended bone fracture.
3Stability of the object's composition
If plate fixation is used to stabilize bones, then bone stability is improved, but increased compressive loading on screws results in hardware failure
Solution Approach 1:
The patent applies preliminary bone grafting to establish initial stability and begin the bone healing process before applying plate fixation. This preliminary action reduces the mechanical burden on the hardware by allowing early bone bridging, thereby decreasing compressive loading on screws and preventing hardware failure.
Solution Approach 2:
The patent changes the mechanical parameters of the fixation system by introducing bone graft material that alters the load distribution. The graft material modifies the stiffness and load-bearing characteristics of the construct, reducing peak stresses on the hardware and improving overall durability.
4Manufacturing precision
If Darco plates with metal block spacers are used for open-wedge osteotomy, then correction is maintained, but boney integration into the spacer is prevented requiring additional graft material
Solution Approach 1:
The patent changes the material properties of the spacer from metal to radiolucent material that permits boney integration. This parameter change allows bone to grow into and through the spacer, eliminating the need for additional bone graft material while maintaining the corrective function.
Solution Approach 2:
The patent uses a radiolucent spacer as an intermediary that facilitates rather than prevents bone integration. This spacer material acts as a temporary structure that bone can grow through and integrate with, ultimately being replaced by bone tissue, thereby eliminating the need for additional grafting procedures.
5Manufacturing precision
If Darco plates are used for open-wedge osteotomy, then correction is maintained, but bone graft material can migrate out of the osteotomy site resulting in non-unions
Solution Approach 1:
The patent employs a radiolucent spacer that functions as a containment structure for the bone graft material. This spacer acts as a flexible barrier that prevents graft migration while allowing bone ingrowth, thereby maintaining correction and ensuring reliable bone union.
Solution Approach 2:
The radiolucent spacer serves as an intermediary barrier that prevents bone graft material from migrating out of the osteotomy site. By introducing this intermediate containment structure, the patent ensures that the graft material remains in position to facilitate reliable bone union while maintaining the desired correction.
6Strength
If Darco plates made of stainless steel and titanium are used, then structural strength is provided, but radiographic studies cannot be performed to evaluate bone healing
Solution Approach 1:
The patent changes the material property of the spacer from radiopaque (metal) to radiolucent. This parameter change allows X-rays and other radiographic imaging to pass through the spacer, enabling clinicians to evaluate bone healing progress without removing or replacing the implant.
Solution Approach 2:
The patent uses composite material construction for the spacer that provides both structural strength and radiolucency. By combining materials with complementary properties, the spacer maintains the necessary mechanical strength to support the osteotomy while allowing radiographic evaluation of bone healing.
Data Source
AI summary
Apparatus for fusing a first bone of a joint with a second bone of a joint, the apparatus comprising:a fusion block comprising a hollow tubular structure characterized by a first end, a second end and a lumen extending from said first end to said second end, the first end being configured to engage the first bone of the joint and the second end being configured to engage the second bone of the joint, the lumen being configured to span the distance from the first bone of the joint to the second bone of the joint and to receive and retain bone graft material therein, whereby to facilitate bone fusion across the fusion block; andat least one fusion plate for connecting the fusion block to the first bone of the joint and the second bone of the joint.