Disc-Shaped Bone Augment With Elastic Segments for Secure Fixation
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Solution Overview
Problem
Existing bone augments for endoprostheses, particularly at the ends of long tubular bones like the tibia, fail to provide a stable and secure fixation to the bone, leading to difficulties in implantation and potential damage during revision surgery, and may grow into the bone, making removal challenging.
Innovation Solution
A disc-shaped augment with a C-shaped configuration and a skeletal design, featuring elastic limbs connected via a joint-like connecting piece, allows for compression and expansion, providing a restoring force that enhances fixation and promotes bone ingrowth, while allowing easy explantation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the augment is designed as a single unitary disc, then the structure is simple, but the compression and elastic behavior are not optimal and fixation security is reduced
Solution Approach 1:
The augment is divided into multiple disc segments (first, second, and third disc segments) that are arranged adjacent to each other and connected via elastic webs to the frame. This segmentation allows each segment to compress independently during insertion, optimizing the elastic behavior and fixation security while maintaining a manageable structural complexity through modular design.
2Reliability
If the augment is compressed during insertion, then primary fixation is achieved, but the risk of growing into the bone and difficulty in removal increases
Solution Approach 1:
The augment incorporates elastic webs connecting the disc segments to the frame, enabling dynamic compression during insertion to achieve primary fixation. The elastic design allows the augment to be compressed into the bone cavity, creating secure initial anchoring. The same elastic properties enable controlled expansion during explantation, facilitating easy removal without damage to the bone head.
3Duration of action of stationary object
If the augment is designed with a porous structure, then bone ingrowth is promoted, but the mechanical strength may be reduced
Solution Approach 1:
The outer shell of the augment is designed with a porous structure that promotes bone ingrowth and long-term fixation. The porous design allows bone material to penetrate and integrate with the augment over time, creating stable long-term anchoring. The porous structure is strategically positioned on the outer shell where it contacts the bone, optimizing bone ingrowth while maintaining sufficient mechanical strength through the overall structural design.
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
The augment achieves favorable primary fixation and supports long-term, stable bone integration by promoting bone ingrowth, simplifying insertion and explantation, and ensuring secure anchoring without damaging the bone.
Implementation Method 1
the connecting piece between the legs is designed in a joint-like manner and interacts elastically with the legs, so that a frame is formed, and upon compression of the legs an outwardly directed restoring force is generated
Data Source
Figure 1~4
Figure 5A~9B
AI summary
The invention relates to a disc-shaped augmentation for filling bone defects, in particular at the end of long bones, such as the tibia, comprising a first side (11), a second side (12), an outer casing (15) on lateral sides and an inner wall for a through-opening (2), running from the first to the second side, for a stabilising keel (8) of an endoprosthesis (9) arranged on the second side. The augmentation is generally C-shaped with two sections (31, 32) flanking the through-opening. According to the invention, a connection part (30) between the flanking sections (31, 32) is designed in an articulated manner and cooperates elastically with the flanking sections (31, 32) such that a frame (39) is formed, and an outward restoring force is generated when the flanking sections (31, 32) are compressed. The flanking sections are designed with a skeleton construction, with multiple disc segments (36) lying next to one another and separated by slots (34) and arranged on the frame via connecting pieces (37). This allows for a high level of compression of the flanking sections, without causing tensions between the disc segments. The skeleton construction allows for particularly advantageous compression behaviour and elasticity. The preload force applied due to the compression achieves optimal securing of the augmentation as the primary fixing. The skeleton structure, with the slots and intermediate spaces, not only allows for high levels of compression, but also encourages ingrowth behaviour of bone material for long-term stable attachment.