Segmented Thread Epiphyseal Plate for Controlled Bone Growth
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Solution Overview
Problem
Existing bone alignment implants for temporary epiphysiodesis or hemiepiphyseodesis lack variability and precision in controlling bone growth, often requiring invasive procedures and resulting in unpredictable growth outcomes due to random alignment and material removal challenges.
Innovation Solution
A plate-shaped, elongated implant with segmented threaded openings, a surface-side groove, and undercut design, featuring claw-shaped extensions and Kirschner wire holes, allowing for controlled bone screw insertion and easy removal, minimizing tissue damage and bone growth interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Blount staples are used for temporary epiphysiodesis, then growth control is achieved through compression, but operative time is extended and invasive material removal is required
Solution Approach 1:
The implant is designed to be removed by simply extracting the plate from the bone surface without requiring invasive removal of embedded staples or clips. The plate can be lifted off with a flat instrument due to the undercut design that prevents bone tissue ingrowth, significantly reducing operative time for removal while maintaining reliable growth control during the implantation period
Solution Approach 2:
The plate is pre-shaped with an undercut on its underside before implantation. This preliminary design feature ensures that when the plate is placed on the bone, the undercut prevents bone tissue from growing over the plate surface, facilitating easy removal later without invasive procedures and reducing overall operative time
2Shape
If plate-shaped implants with openings for diverging screws are used, then alignment is achieved, but control over bone growth becomes random and less precise
Solution Approach 1:
The plate features a specifically designed breakthrough (opening) in its center with a predetermined orientation relative to the longitudinal axis. This localized feature provides a reference point that ensures precise and reproducible control over bone growth direction, eliminating the randomness associated with diverging screw openings while maintaining proper alignment
3Ease of operation
If weakened sections are added to the plate, then ease of removal is improved, but structural integrity may be compromised
Solution Approach 1:
Instead of weakening the plate by removing material from its top surface (which would compromise strength), the undercut is created on the underside of the plate. This dimensional approach allows the plate to maintain full structural integrity on the bone-contacting surface while the undercut on the opposite side facilitates easy removal by preventing bone tissue ingrowth and allowing the plate to be lifted off with a flat instrument
Data Source
Figure 1a~1h
Figure 2a~2h
Figure 3a~3h
AI summary
The invention relates to an implant for temporary epiphysiodesis or hemiepiphysiodesis, consisting of a plate-shaped, elongated body with at least two openings (2, 3) for receiving bone screws, wherein the plate-shaped body has a weakened section and an opening (4) in the area between the openings, which is surgically positioned on the epiphyseal plate. According to the invention, the openings are provided with at least a single-start thread, the thread being segmented such that unthreaded sections (6) remain on the inner circumference between threaded sections (5). Furthermore, at least one bore (7) for receiving a Kirschner wire is provided at each end of the plate-shaped body. According to the invention, the weakened section is designed as a groove (8) which intersects the opening on the upper surface of the plate and runs substantially perpendicular to the longitudinal axis of the plate.The underside of the plate has at least one undercut (11) in the area between the openings with segmented thread.