Temporary Threaded Bone Pin Halves for Hammertoe Alignment
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Solution Overview
Problem
Current surgical methods for correcting hammer toe and other digital deformities using permanent prosthetic devices or K-wires can lead to post-surgical misalignment, swelling, inflammation, and infection, and are not suitable for conditions requiring temporary anatomical alignment for healing.
Innovation Solution
A pair of self-tapping, interconnecting, externally and internally threaded cylindrical bone pin halves that draw and hold bone segments together without radial outward forces, promoting bone regeneration and faster healing through interlocking hook threads and adjustable clamping load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If permanent prosthetic devices or K-wires are used for anatomical alignment, then the alignment stability is improved, but post-surgical complications (swelling, inflammation, infection) increase
Solution Approach 1:
The bone pin is divided into two separate halves that are inserted into separate bone segments and then joined together. This segmentation allows the device to be removed after healing without requiring a second surgical procedure to extract a permanent implant, thereby reducing long-term complications while maintaining alignment stability during the healing period.
Solution Approach 2:
The invention changes the temporal parameter of the implant by making it temporary rather than permanent. The bone pin is designed to be in place only during the healing period (typically 4-6 weeks) and then removed, changing the duration parameter from indefinite to specific, which reduces the window for complications to occur.
2Stability of the object's composition
If K-wire is driven across the joint, then the joint alignment is maintained, but misalignment due to wire distraction occurs
Solution Approach 1:
The bone pin halves feature rounded ends and smooth contours that allow them to be driven into the bone without creating stress concentration points. The curved geometry of the pin halves distributes forces more evenly along the bone interface, preventing the distraction and misalignment issues associated with sharp-edged K-wires.
Solution Approach 2:
The two separate bone pin halves are joined together using an interference fit or mechanical connection, merging them into a single functional unit that spans the joint. This combined structure provides more reliable alignment maintenance compared to a single K-wire, as the distributed connection points resist distraction forces more effectively.
3Strength
If permanent materials are used for prosthetic devices, then device strength is improved, but bone regeneration is inhibited
Solution Approach 1:
The bone pin is designed as a temporary implant that is discarded after it has served its purpose of maintaining alignment during bone healing. By removing the implant after 4-6 weeks, the bone can continue to regenerate and remodel without the foreign body present, eliminating the long-term inhibition of bone regeneration while maintaining device strength during the critical healing period.
Solution Approach 2:
The bone pin is designed as a disposable, short-term implant rather than a permanent device. This approach allows the use of strong materials that provide adequate strength during the healing period, while the temporary nature of the implant eliminates the need for long-term biocompatibility concerns and allows complete bone regeneration afterward.
4Strength
If threaded bone pin halves are used, then bone segment connection strength is improved, but radial outward forces may cause cracking
Solution Approach 1:
The bone pin halves are designed with thread profiles that gradually engage the bone, cushioning the insertion process. The threads are configured to cut into the bone progressively rather than forcing immediate engagement, which cushions against radial outward forces that could cause cracking. The gradual engagement allows bone material to be displaced slowly and controlled.
Solution Approach 2:
The bone pin is made from composite or multi-phase materials that combine strength with flexibility. This allows the pin to provide strong connection between bone segments while the material composition absorbs and distributes radial stresses, preventing the transmission of harmful spreading forces to the bone.
Data Source
AI summary
An orthopedic drill bit includes a cutting head formed to include diametrically opposed cutting lips leading to a central point and away to a radiused periphery to center said bit. The drill includes flutes extending from a cutting end, said flutes having a dulled periphery to prevent out of round holes. The flute design increases in width progressively from the tip up the shank, to maintain an adequate and unrestricted space for chips to easily move upward, preventing the chips from being compressed into a smaller opening while maintaining the tapered depth of the flutes for strength.