Multi-Component Implant Peg for Ankle Bone Stability
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Solution Overview
Problem
In total ankle replacement surgeries, the quality of bone into which implant pegs are inserted can be poor, posing challenges for secure attachment of bone implants.
Innovation Solution
An implant system comprising an implant plate with a plurality of openings and independently positionable pegs, where each peg has a peg body and a retaining device, allowing for secure attachment to resected bone through peg holes drilled at varying angles and diameters, with retaining devices extending through the plate to ensure stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional single-component pegs are used in poor quality bone, then the implant attachment is simple, but the stability and reliability of the attachment is insufficient
Solution Approach 1:
The peg is divided into multiple independent components: a peg body for insertion into the bone, a retaining device with connecting portion extending through the implant plate, and a fastening mechanism. This segmentation allows each component to perform its specific function optimally - the peg body provides anchorage in poor quality bone, the retaining device spans the implant plate to distribute loads, and the fastening mechanism secures the assembly. The modular structure improves attachment reliability without requiring the entire peg structure to be complex.
Solution Approach 2:
The retaining device is positioned within the peg structure, with its connecting portion extending through the implant plate while the fastening mechanism nests within the peg body or connecting portion. This nested arrangement allows multiple functional elements to be integrated in a compact configuration, improving attachment stability while controlling overall structural complexity through efficient space utilization.
2Adaptability or versatility
If pegs with fixed dimensions are used, then the manufacturing process is simple, but the adaptability to varying bone quality and angles is poor
Solution Approach 1:
The peg system incorporates variable parameters including different peg body diameters, lengths, and geometries to match different bone qualities and drilling angles. The retaining device can be configured with varying connecting portion lengths and orientations. By designing the system to accommodate parameter variations, the implant achieves high adaptability to patient-specific anatomy and bone conditions while maintaining standardized manufacturing processes for each size variant.
Solution Approach 2:
The multi-component peg design creates a universal system where the same basic structure (peg body + retaining device + fastening mechanism) can be adapted to various bone qualities and angles by changing specific dimensional parameters rather than requiring entirely different designs. The retaining device's connecting portion can extend through the implant plate at different orientations, and the fastening mechanism works across all variants, providing universality while managing manufacturing complexity through modular design.
3Strength
If the peg body transverse dimension is larger than the implant plate openings, then the peg provides better anchorage in bone, but the assembly and positioning becomes more difficult
Solution Approach 1:
The peg system separates the anchorage function (peg body with large transverse dimension for bone grip) from the assembly function (retaining device with connecting portion that fits through implant plate openings). The peg body can have optimized dimensions for bone anchorage without being constrained by the size of implant plate openings, since the retaining device mediates the connection. This segmentation allows strong anchorage while maintaining ease of assembly through the retaining device's intermediate role.
Solution Approach 2:
The retaining device acts as an intermediary between the large-diameter peg body and the implant plate openings. The connecting portion of the retaining device fits through the openings to secure the peg body, which has dimensions optimized for bone anchorage rather than for passing through the plate. This intermediary structure enables the peg to have large transverse dimensions for strength while the assembly process remains easy, as the retaining device facilitates connection through the plate openings.
Data Source
Figure 1
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AI summary
An implant system comprises an implant plate adapted to be positioned on a surface of a resected bone. The implant plate has a plurality of openings. A plurality of independently positionable pegs attach the implant plate to the bone. Each peg has a longitudinal axis and comprises: a peg body and a retaining device. The peg body is inserted into a peg hole in the bone. The peg body has a transverse dimension in a direction normal to the longitudinal axis, the transverse dimension larger than the openings of the plate. The retaining device is separate from the peg body, and is configured to attach to the peg body, with at least a first portion of the retaining device positioned above an upper surface of the implant plate, and a connecting portion of the retaining device extending through one of the openings of the implant plate.