Longitudinal Bone Implant with Segmented Ribs for Rotational Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing bone implants face challenges in providing stability, especially rotational stability, and often displace spongiosa excessively, leading to impaired fixation and increased complexity in surgical procedures, particularly in high mechanical load areas like the femur neck.
Innovation Solution
A longitudinal bone implant with a substantially circular cross-sectional profile featuring a front section with alternating longitudinal groove-like cut-outs and radially protruding ribs, where the ribs have increased width further from the central axis, minimizing spongiosa displacement and enhancing rotational stability without the need for threads, allowing for optimal force distribution and bone preservation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a threaded proximal part with relatively great diameter is used, then the interaction surface with the bone is increased, but the displacement of spongiosa is substantial and rotational stability is not achieved
Solution Approach 1:
The proximal part is segmented into multiple longitudinal blades separated by groove-like cut-outs. This segmentation allows the implant to interact with the bone through multiple discrete contact points rather than a continuous threaded surface, reducing the volume of spongiosa that must be displaced while maintaining adequate interaction surface area through the combined surface of all blades
Solution Approach 2:
The blades have varying cross-sectional widths with different local properties - wider at the front end for initial bone engagement and insertion, and narrower towards the rear for reduced displacement. This local variation in geometry allows optimal interaction with the bone at different locations along the blade length while minimizing overall spongiosa displacement
2Quantity of substance
If helically twisted blades are used, then the interaction surface with spongiosa is increased, but lateral movement induces rotation of the fracture through helical twist
Solution Approach 1:
Instead of using helically twisted blades that convert lateral movement into rotation, the invention uses longitudinally oriented straight blades. This inverts the approach by eliminating the helical twist mechanism while maintaining adequate interaction surface area through the longitudinal orientation and varying cross-sectional widths of the blades, thereby preventing fracture rotation
3Stability of the object's composition
If a non-circular cross-sectional profile with flat sides is used, then rotational stability is achieved, but the implant cannot be used with intramedullary nails having circular transversal bores
Solution Approach 1:
The blades create an asymmetric interaction with the bone through their varying cross-sectional widths and longitudinal orientation, providing rotational stability. However, the overall cross-sectional profile of the implant remains substantially circular, maintaining compatibility with circular transversal bores of intramedullary nails. The asymmetry is achieved functionally through the blade configuration rather than through the overall geometric shape
4Reliability
If multiple screws are inserted through multiple transversal bores, then rotational instabilities are addressed, but the surgical procedure complexity increases
Solution Approach 1:
The invention combines multiple blade elements into a single integrated implant structure that provides rotational stability through the collective action of the blades. This merges the function of multiple screws into one device, achieving rotational stability without requiring multiple separate insertion procedures or multiple transversal bores, thereby reducing surgical complexity
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to a longitudinal bone implant with a substantially circular cross- sectional profile, comprising a front section having a front end and a shaft section having a rear end, wherein the front section comprises at least three longitudinal groove-like cut- outs extending in the axial direction of the front section and opening towards the front end of the implant, circumferentially alternating with at least three longitudinal, radially protruding ribs extending in an axial direction, wherein the ribs have an increased cross- sectional width in the section radially more distant to the central longitudinal axis of the implant as compared to the width in a section radially closer to the central longitudinal axis of the implant. Furthermore, the invention relates to uses of the implant and methods that employ the implant.