Osteochondral Graft Fixation via Radial Bone Compression
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Solution Overview
Problem
Current methods for repairing damaged articular cartilage in the knee joint, such as osteochondral transplantation, face challenges with graft stability and integration due to issues with hole size and cellular damage during implantation.
Innovation Solution
A graft implantation technique involving a dilator with a tapered hollow body member and radial slits is used to create a recipient hole slightly smaller than the graft, allowing for radial expansion to securely fit and compress the graft, preventing movement and promoting integration with surrounding tissues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the recipient hole is made larger to facilitate graft insertion, then the ease of operation is improved, but the graft stability deteriorates as the graft can rotate and become loose
Solution Approach 1:
The dilator transforms the static recipient hole into a dynamic, expandable structure. The hollow frusto-cone dilator is inserted into the drilled hole and expanded radially outward to form an enlarged recipient hole with compressed bone walls, allowing the graft to be securely held in place while maintaining ease of insertion
Solution Approach 2:
The invention changes the physical parameters of the recipient hole by using the dilator to expand the hole's diameter and compress the bone walls. This creates a hole that is larger than the original drilled hole but provides a secure fit for the graft, resolving the contradiction between ease of insertion and graft stability
2Reliability
If the recipient hole is made smaller to secure the graft, then the graft stability is improved, but the cellular damage worsens during implantation
Solution Approach 1:
The dilator performs preliminary action by expanding the recipient hole and compressing the bone walls before the graft is inserted. This preliminary preparation creates an optimal environment that secures the graft while minimizing cellular damage during the actual implantation process
Solution Approach 2:
The dilator acts as an intermediary tool between the drilled hole and the graft. It transforms the small drilled hole into an enlarged recipient hole with compressed walls, mediating between the need for a secure fit and the need to minimize cellular damage during graft insertion
3Reliability
If the bone walls are compressed to secure the graft, then the graft stability is improved, but the device complexity increases
Solution Approach 1:
The device is segmented into distinct functional components: the hollow frusto-cone dilator with radial slits for expansion, and the graft placement mechanism. This segmentation allows the compression function to be achieved through a specialized dilator rather than a complex integrated system
Solution Approach 2:
The hollow frusto-cone dilator functions as a flexible expansion device that can be inserted through a narrow profile and then expanded radially to compress the bone walls. This flexible shell design allows the device to achieve wall compression without requiring complex mechanisms
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method ensures stable graft placement and integration by expanding the recipient hole to securely fit the graft, preventing rotation and cellular damage, thereby enhancing the healing process.
Implementation Method 1
The dilator is pushed into the opening until the outer surface of the dilator engages the inner wall of the opening and exerts outwardly-directed radial forces against the opening to expand the opening and compress the bone and tissue walls defining the opening
Data Source
AI summary
A surgical procedure for implanting a graft according to which a dilator is inserted in a recipient opening and the graft is inserted in the dilator to cause outward expansion of the dilator into engagement with the portion of a bone surrounding the opening. After the dilator is removed from the opening, the bone surrounding the opening collapses around the graft to secure the graft in the opening.